
DEPARTMENT OF THE INTERIOR 


BUREAU OF MINES 


JOSEPH A. HOLMES. Djrrcto* 


VOLATILE MATTER OF 
COAL 


HORACE C. PORTER 


F. K. OVITZ 






WASHINGTON 

government printing office 







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Bulletin I 


DEPARTMENT OF THE INTERIOR 

BUREAU OF MINES 

»• 

JOSEPH A. HOLMES, Director 


THE VOLATILE MATTER OF 
COAL 


BY 

HORACE C. PORTER 

AND 

F. K. OVITZ 



WASHINGTON: 

GOVERNMENT PRINTING OFFICE 
1913 


Third edition, May, 191S. 

First edition issued in October, 1910. 


D, or 0. 

JUiJ 17 J9I3 




CONTENTS. 





< 


Page. 


* Introduction. 5 

Scope of report.. 5 

Summary of results. 5 

Definition of volatile matter. 6 

Object of investigation. 0 

Bearing on boiler-furnace operation. 7 

Bearing on smoke production. 9 

Bearing on locomotive firing. 10 

Bearing on gas-producer, coke-oven, and gas-retort operation. 10 

Nature of coal substance. 11 

Effect of oxygen in coal on calculation of heat value from ultimate analysis. 11 

Related investigations by others. 12 

Experimental plan of present investigation. 13 

Methods. 14 

Collection and preparation of samples. 14 

Tests in iron retort. 15 

Apparatus. 15 

Operation. 17 

Tests in platinum retort. 19 

Apparatus. 19 

Operation. 21 

Methods of gas analysis. 22 

CO 2 , 0, illuminants, CO. 22 

Benzene. 22 

Hydrogen. 23 

Methane and homologues. 23 

Summary and interpretation of results. 25 

Coals tested. 25 

Tests of coal in iron retort for by-products of coking. 26 

Summaries of tests. 26 

Effect of moisture in coal on ammonia yield. 27 

Variation in gas composition during test. 28 

Inert volatile matter. 28 

Tests of coal in platinum retort. 29 

Total gas at various temperatures. 29 

Volatile matter during early period of heating at various temperatures. 33 

Tabulated results, early volatile matter. 35 

Conclusions from results. 41 

Volatile matter at ordinary temperature and at 105° C. 41 

Temperature in “official” volatile-matter determination. 42 

Calculation of heat value of coal from ultimate analysis. 42 

Detailed data of individual tests. 45 

General summary. 55 

Addenda. 56 

Publications on fuel technology. 57 


3 














































TABLES. 


Page. 

Table 1 . Steaming tests of various coals. 8 

2. Gas obtained by distillation of three typical American coals. 12 

3. Source of coal samples used in tests. 25 

4. Analyses of coals tested. 25 

5. Results of by-product tests. 26 

6 . Tests of coal from Sheridan field, Wyo. (lab. No. 11), computed to 

dry basis. 27 

7. Comparative by-product tests of dry and wet coal. 28 

8 . Total gas yield and composition at different temperatures. 29 

9. Yield of different gaseous products at 500°, 700°, and 1 , 000 ° C. 30 

10. Volatile matter in ten minutes’heating of 10 grams of air-dried coal.. 38 

11 . Quantities of different gases from ten minutes’ heating of air-dried 

coal. 39 

12. Early volatile products in second series of tests. 40 

13. Volumes of various gases produced in second series of tests. 40 

14. Oxygen relations in volatile matter. 43 

15. Results of by-product tests of 400 grams of coal. 45 

16. Analyses of samples of gas obtained successively during by-product 

tests. 46 

17. Analyses of total gas from by-product tests. 47 

18. Total gas obtained from 10 grams of air-dried coal. 47 

19. Early volatile products from ten minutes’ heating of 10 grams of air- 

dried coal. 49 

20. Early volatile products in second series of tests (heating 10 grams of 

air-dried coal to definite temperatures). 52 

21. Tar and heavy hydrocarbons (smoke producers) obtained at different 

furnace temperatures. 56 


ILLUSTRATIONS. 


Page. 

Plate I. A, Apparatus used in distilling 400-gram samples of coal in iron 
retort; R, Apparatus used in distilling 10-gram samples of coal in 

platinum retort. 18 

Figure 1 . Section of iron retort and section of large electric furnace. 16 

2. Section of small electric furnace and platinum retort, and section 

of air bath. 20 

3. Total quantities of different gases from 10 grams of air-dried coal at 

different temperatures. 31 

4. Smoky constituents of early volatile matter; 10 grams of air-dried 

coal heated ten minutes. 32 

5. Oxides of carbon in early volatile matter; 10 grams of air-dried coal 

heated ten minutes. 33 

6 . Combustible gases and tar in early volatile matter; 10 grams of air- 

dried coal heated ten minutes. 34 

7. Inert or noncombustible constituents (including moisture) of early 

volatile matter; 10 grams of air-dried coal heated ten minutes.. 35 

8 . Smoky constituents of early volatile matter; 10 grams of air-dried 

coal heated to definite temperature. 36 

9. Combustible gases and tar in early volatile matter; 10 grams of 

air-dried coal heated to definite temperature. 37 

4 




































THE VOLATILE MATTER OF COAL. 


By Horace C. Porter and F. K. Ovitz. 


INTRODUCTION. 

SCOPE OF REPORT. 

The various fuel investigations that were being carried on by the 
technologic branch of the United States Geological Survey were 
transferred by law on July 1, 1910, to a new federal bureau, the 
Bureau of Mines, that was authorized to continue the investigations 
and make public reports of the results. In consequence of this 
transfer, the following report is published as a bulletin of the new 
bureau. 

The United States Geological Survey had been engaged in analyzing 
and testing coals, lignites, and other mineral fuel substances under 
authority given by act of Congress. This work, now centered at 
the experiment station at Pittsburgh, Pa., had its beginning in the 
operations of the coal-testing plant erected at the Louisiana Purchase 
Exposition in St. Louis, Mo., in 1904. The results obtained at that 
plant showed that the work of determining the fuel value of the coals 
and lignites in the United States with a view to increasing efficiency 
in their utilization would be incomplete if it did not include systematic 
physical and chemical researches into the processes of combustion. 
Hence in its later investigations the Survey carried on such re¬ 
searches, concentrating attention on those lines of inquiry which 
promised results of greatest economic importance. 

This bulletin is a report on an investigation of the volatile matter 
in several typical coals—its composition and amount at different tem¬ 
peratures of volatilization. As the investigation is still in progress 
and will doubtless include other coals than those already examined, 
the bulletin may be considered a preliminary report; stating the prob¬ 
lems studied, the methods used, and the results thus far obtained. 

SUMMARY OF RESULTS. 

The investigation has already shown that the volatile content of dif¬ 
ferent coals differs greatly in character. The volatile matter evolved 
from the younger coals of the West includes a large proportion of 

5 




6 


THE VOLATILE MATTER OF COAL. 


carbon dioxide, carbon monoxide, and water, and a correspondingly 
small proportion of hydrocarbons and tarry vapors. The older bitu¬ 
minous coals of the Appalachian region yield volatile matter con¬ 
taining large amounts of tarry vapors and hydrocarbons, difficult to 
burn completely without a considerable excess of air and a high tem¬ 
perature. Coal of the western type, moreover, gives up its volatile 
matter more easily at moderate temperatures than coal of the eastern 
type. The volatile matter produced at medium temperatures is 
rich in higher hydrocarbons of the methane type, such as ethane 
and propane, which contain a larger proportion of carbon than is 
present in methane. These facts help to explain the difficulty of burn¬ 
ing Pittsburgh coal, for example, without smoke, the low efficiency 
usually obtained in burning high-volatile western coals, the advan¬ 
tage of a preheated auxiliary air supply introduced over a fuel bed^ 
and the advantage of a furnace and boiler setting adapted to the 
type of fuel used. They bear directl}^ also on the question of steaming 
“capacity’^ of coals for locomotives, the designing and operation of 
gas producers for high-volatile fuels, and the operation of coke ovens 
and gas retorts. 

The results show further that certain bituminous coals of the interior 
and Rocky Mountain provinces give promise of good yields of by¬ 
products of coking, notably ammonia and high-candlepower gas, 
comparing favorably in these respects with the high-grade coking 
coals of the eastern province. 

They show also that inert, noncombustible material is present in 
the volatile products of different kinds of coal to an extent ranging 
from 1 to 15 per cent of the coal. 

DEFINITION OF VOLATILE MATTER. 

The term ‘^volatile matterin coal, as distinguished from the 
term ‘Volatile combustible matter,’’ maybe criticized on the ground 
that moisture is volatile and would therefore by implication be 
included in the term “volatile matter.” On the other hand, the 
present investigation shows that the volatile matter exclusive of 
“moisture” contains considerable percentages of noncombustible 
materials, such as carbon dioxide, water, and nitrogen, and the appli¬ 
cation of the term “combustible” is therefore hardly justifiable. 
Less confusion seems likely to result from designating the volatile 
matter exclusive of moisture “volatile matter,” even though moisture 
is also volatile, than would result from applying the term “combus¬ 
tible” to material which is one-tenth to one-third noncombustible. 

OBJECT OF INVESTIGATION. 

Methods for the quantitative estimation of volatile matter have not 
entered into the present investigation, the object of which has been 
rather to determine the composition of the volatile matter evolved at 


INTRODUCTION. 7 

different temperatures from different types of coal and to show the 
influence of this factor on efficiency in the use of coal. 

BEARING ON BOILER-FURNACE OPERATION. 

If a furnace produces 15 pounds of flue gases from 1 pound of fuel, 
and if these gases, by reason of improper firing or furnace setting, con¬ 
tain unconsumed combustible gases to the extent by volume of 0.5 per 
cent of CO, 0.5 per cent of H, and 0.4 per cent of CH^, the theo¬ 
retical loss through these materials is approximately 10 per cent of 
the heating value of the coal. For every 0.1 per cent of CO in the 
flue gas the efficiency is lowered theoretically 0.47 per cent; for 0.1 
per cent of H, 0.48 per cent; and for 0.1 per cent of CH^, 1.52 per cent. 

In the report entitled “A study of four hundred steaming tests 
it is shown that in 48 tests made at the St. Louis fuel-testing plant 
of the Geological Survey, as the CO in the flue gas increased from 0.3 
to 0.7 per cent the efficiency dropped from 65 to 57 per cent—about 
2 per cent for each 0.1 per cent of CO, or four times the above-stated 
theoretical drop. The amounts of H and CH4 in the flue gas were 
not determined in these tests. In the discussion of the relation be¬ 
tween efficiency and CO, however, the following statement is made: 
^‘We therefore reach the inevitable conclusion that at least two-thirds 
of the large drop in code ‘boiler efficiency^ with rise of CO is due to 
incomplete combustion losses not represented by CO, so that high CO 
is a decided danger signal.’^ Very few records of determinations of 
hydrocarbons or hydrogen in flue gases are to be found, presumably 
because of the analytical difficulty in determining such small quanti¬ 
ties. In the report of the Manchester (England) Smoke Committee, 
1895,^ are given some flue-gas analyses showing in certain tests of 
hand-fired furnaces 0.25 to 0.40 per cent of CH4 and 0 to 1 per cent 
of H. Recent tests at the Geological Survey’s plant on small house¬ 
heating boilers using Pittsburgh slack coal have given in the flue gases 
as high as 2.8 per cent of CO and nearly 1 per cent each of H and 
CH4, the conditions in these tests being, however, extremely unfav¬ 
orable to complete combustion and not parallel to those in larger 
plants. There seems to be a strong probability, nevertheless, that in 
the greater number of smoking chimneys volatile combustible gases 
are escaping which carry from 3 to 10 per cent of the total heat value 
of the fuel; and it is easy to see the importance of improving methods 
for the analytical determination of methane and hydrogen in flue gas 
and of devising a method whereby samples may be taken which are 
less diluted with air, in order that the CO, CH4, and H may appear 
as larger percentages. 


O Bull. U. S. Geol. Survey No. 325,1907, pp. 28, 65. 

6 Cited in Bull. U. S. Geol. Survey No. 334, 1908, p. 14. 



8 


THE VOLATILE MATTER OF COAL. 


E. J. Constam and P. Schlapfer,® in an extended series of boiler 
trials of European coals, using the internally fired marine type of 
boiler, have shown in a striking manner the effect of the amount and 
composition of the volatile matter on the boiler efficiency. They 
found in the flue gas from one coal 3.5 per cent of CO, and 1.5 per 
cent of H, which caused an efficiency loss of 17.2 per cent. 

Several factors may enter into the unaccounted-for losses in the 
heat balance of a steaming test. For example, it is likely that more 
heat is carried away by the flue gases (including steam) than is usu¬ 
ally charged to them, for the reason that their specific heat probably 
increases with temperature; and this factor is of special importance 
for low-grade, high-moisture, high-oxygen coals. Another factor is 
the loss of solid combustible material in the chimney gas, or “spark¬ 
ing,’’ which also is more prevalent with low-grade fuels. That the 
most important “unaccounted-for loss,” however, is likely to be 
found in the unburned volatile gases which are allowed to escape 
through lack of sufficient combustion space or of a sufficient supply 
of heated air, the above considerations are intended to show. The 
present paper confirms and explains the known facts that in order to 
obtain high efficiency the furnace must be adapted to the fuel and 
that the character, as well as the amount, of volatile products is of 
decided importance. The following results of steaming tests made 
at the Geological Survey’s plant, compared with some results from 
the present investigation on the character of the volatile matter in 
the coals used, will further illustrate this point: 


Table 1.— Steaming tests of various coals. 


Coal No. 

Volatile 
matter 
in dry 
coal (per 
cent). 

Combus¬ 
tible gas 
at 000°.o 

Heavy 
hydro¬ 
carbon 
gases at 
600°.o 

Steam 
test No. 

Boiler 

efficiency 

(per 

cent). 

Unac¬ 
counted- 
for loss 
(per 
cent). 

CO in flue 
gas (per 
cent). 

Rate of 
fir ing. i> 

W. Va. 11. 

20.8 

60 

5.6 

56 

68.3 

5.4 

0.05 

18.1 

Pa. 19. 

32.9 



(498 

63.9 

8.7 

.04 

20.4 





\308 

65.6 

7.1 

.02 

21.0 

Lab. 3. 

30.4 

75 

8.5 






Ill. 19. 

33.0 

108 

10.5 

160-63 

63.7 

12.5 

.19 

19.0 

W. Va. 13. 

32.6 

116 

13.8 

179-80 

68.1 

11.1 

.14 

15.7 

Wyo. 4. 

45.4 



399 

56.4 

15.9 

.07 

24.0 

Lab. 18. 

43.4 

142 

19.4 


Wyo. 1. 

43.8 

165 

15.1 

63 

54.9 

11.2 

.25 

22.7 

Tex. 4. 

41.6 



(291 

59.9 

6.9 

.0 

23.1 





\298 

51.2 

17.6 

.0 

35.2 


o Volume in cubic centimeters from 10 grams in ten minutes, laboratory test. 
b Pounds of dry coal per square foot of grate surface per hour. 


W. Va. 11. Pocahontas bed, “smokeless” coal. 

Pa. 19. Pittsburg bed, Westmoreland County. 

Lab. 3. Pittsburg bed, Connellsville, Fayette County, Pa., similar to Pa. 19. 

Ill. 19. No. 7 seam, Zeigler, Franklin County. 

W. Va. 13. “No. 2 gas coal,” Page, Fayette County. 

Wyo. 4. Bituminous coal, Hanna, Carbon County. 

Lab. 18. Bituminous coal, Diamondville, Uinta County, Wyo., somewhat similar to Wyo 4 
Wyo. 1. Subbituminous, Sheridan district, 22 per cent moisture. 

Tex. 4. Lignite, Wood County, 36 per cent moisture. 


Zeitschr. Ver. deutsch. Ing., vol. 53,1909, pp. 1837, 1880, 1929, 1972. 































INTRODUCTION. 


9 


Inasmuch as the values given for unaccounted-for losses in a steam¬ 
ing test embody all the errors of the other determinations, little 
dependence can be placed on any relation shown under that heading. 
The relations shown, however, under boiler efficiency, CO, and rate of 
firing, as compared to ease of liberation of volatile gases, are instruc¬ 
tive. Wyo. 1, for example, compared with W. Va. 11, was burned 
with low efficiency, high CO, and high unaccounted-for loss, while in 
the laboratory test its gases were liberated much more easily. The 
rate of firing is an important factor. Coals of low heating value must 
be fired at a high rate in order to maintain a given boiler capacity, 
and as these coals are commonly high in volatile matter, the danger 
of loss of volatile gases is correspondingly great. W. Va. 13, in the 
table above, was fired at a low rate, which may account for the fact 
that it shows high efficiency, even though its volatile gases are easily 
liberated. 

BEARING ON SMOKE PRODUCTION. 

Visible smoke consists of solid carbon particles and solid or liquid 
hydrocarbon particles or ‘‘tar vapors.’’ Both result from incom¬ 
plete combustion of the volatile products of the fuel. The carbon 
of the smoke is not derived from free carbon in the fuel, but is 
deposited by the cooling of hot dissociated hydrocarbon gases. 
Flame is a phenomenon accompanying the chemical union of cer¬ 
tain gases, one of which is usually oxygen; ® and the incandescent 
particles make a flame visible. If some of these particles in the flame 
are carbon, formed by the dissociation of hydrocarbons, luminosity 
results; and if the temperature of these particles is reduced below 
the point at which they combine with oxygen, or if sufficient oxygen 
is not at hand to effect the union, they fail to unite with ox3^gen and 
pass off as solid carbon in smoke. These principles are stated very 
clearly by L. P. Breckenridge in “How to burn Illinois coals without 
smoke.” ^ When a coal produces rich volatile gases, bearing large 
amounts of heavy hydrocarbons, a comparatively large combustion 
space must be provided to allow the flame to be burned out before 
striking cool surfaces; and the flame must have an adequate supply 
of air at an adequate temperature if it is to be burned out in time. 
Furthermore, when rich volatile products distill rapidly from a coal 
at medium and low temperatures, they must be taken care of by 
increased combustion space or by decreased rate of firing. The essen¬ 
tial requirements of smokeless combustion are therefore three: (1) 
Sufficient combustion space, (2) sufficient air at a high temperature, 
and (3) sufficient thorough mingling of gases and air—these three 
conditions to be adapted to the type of fuel and the nature of its 
volatile products. Tabulated data and comparisons are given else¬ 
where in this paper (pp. 32-40) which bear upon the smoke-producing 
tendencies'^ of the coals tested. 

a Lewes, V. B., The luminosity of coal-gas flames: Proc. Roy. Soc., vol. 57, 1895, p. 450. 

b Bull. 15, Univ. Illinois Eng. Exper. Sta., p. 7. 

c See Addenda, p. 56. 

90147°—Bull. 1—13-2 




10 


THE VOLATILE MATTER OF COAL. 


BEARING ON LOCOMOTIVE FIRING. 

For locomotive use that coal is most desirable which will give the 
highest boiler efficiency when burned so as to produce the required 
high evaporative rate (11 to 14 pounds of water per square foot of 
boiler heating surface per hour). Keduction of boiler efficiency 
under these conditions may be due to several causes, chief among 
them being loss of sensible heat, loss of cinders, and loss of com¬ 
bustible gases through the stack. That the last-named factor is of 
large influence it seems safe to conclude from the general rule that 
high rate of firing involves increase of unconsumed combustible 
gases in the flue gas. In view of the high rate of firing and the small 
combustion space in a locomotive, the bearing of the nature of the 
volatile products of the fuel on the completeness of their combustion 
under these unfavorable conditions may readily be seen. 

BEARING ON GAS-PRODTJCER, COKE-OVEN, AND GAS-RETORT 

OPERATION. 

At the top of the fuel bed in a gas producer the volatile products 
of the fuel are distilled. In many types of producer these products 
are distilled at medium and low temperatures, and those of some 
high-volatile fuels contain such large amounts of tar and heavy 
hydrocarbons that it is necessary to draw them downward through 
the hot fuel and convert them into permanent gases in order to 
avoid losses through the deposition of tar and soot. The value of a 
knowledge of the nature of the volatile products from different fuels 
is evident. 

The carbonization of coal in coke ovens and gas retorts is chem¬ 
ically an exceedingly complex process. It involves the distillation 
of volatile products at all temperatures from 100° to 1,200° C. The 
composition of the final volatilized product is determined not only 
by the temperature within the distilling substance, but also more 
largely by the temperature of the region through which the products 
pass. This composition is a resultant of the distillation of many coal 
particles, each probably at a different temperature, and of the time 
and temperature conditions to which the first products are subjected 
after leaving their original state of combination in the coal sub¬ 
stance. The bulk of the mass heated and the rate of supply of heat 
from without determine the time and temperature conditions to 
which the products are subjected. In the study of industrial coal- 
carbonization processes, coke ovens, horizontal gas retorts, and 
vertical retorts, therefore, a knowledge of the variation among coals 
in the nature of their resultant volatile products at different maxi¬ 
mum temperatures should aid in fixing the most favorable working 
conditions. The results presented in this paper show that the first 
products when coal is gently heated without access of air are CO3 


INTRODUCTION. 


11 


and saturated paraffin hydrocarbons. From coking and gas coals 
the latter are formed in abundance, and it is from their decomposi¬ 
tion at high temperatures that t^ie various constituents of coal gas 
and coal tar are formed. Highly oxygenated coals produce large 
quantities of CO2 and CO. 

NATURE OF COAL SUBSTANCE. 

The products of the thermal decomposition of certain types of 
chemical compounds are known, and thus by a study of destructive 
distillation an insight may be gained into the chemical nature of coal. 
A more promising method of attacking the problem seems to be that 
of extraction with solvents or modification of the substance by treat¬ 
ment with chemical reagents, together with systematic microscopical 
examination. Such investigations are now being carried on in the 
laboratories of the Bureau of Mines. It is hoped that with the results 
of these studies the data on destructive distillation afforded by the 
present investigation may be coordinated in such a way as to aid in 
throwing light on the problem. 

EFFECT OF OXYGEN IN COAL ON CALCULATION OF HEAT VALUE 
FROM ULTIMATE ANALYSIS. 

Oxygen, as well as ash, moisture, and nitrogen, exercises an anti- 
calorific influence on coal. Not only is it a diluent, or so much “ dead 
weight,’’ like the other three constituents mentioned, but it also neu¬ 
tralizes or renders ineffective an equivalent combining weight of car¬ 
bon, hydrogen, or sulphur. In some coals this neutralizing action 
may be accompanied by the development of heat, for it is known 
that in destructive distillation exothermic reactions take place.® 
But oxygen is nevertheless in combination in the coal substance and 
must therefore be considered as rendering inert a certain portion of 
the fuel elements. In all the applications of fuel the first stage in 
the decomposition is probably the distillation of the volatile products, 
and as hydrogen has a higher calorific value than an equivalent 
weight of carbon, the distribution of oxygen between carbon and 
hydrogen in the volatile products has a direct influence on the calorific 
value of the fuel. Available hydrogen has greater value than avail¬ 
able carbon. P. L. Dulong’s method of calculating heat value reduces 
the available hydrogen by the amount which would combine with all 
the oxygen, and therefore gives too Iowa value in coals which distribute 
a large proportion of their oxygen to carbon rather than to hydrogen. 
The experimental results given in this paper show that in certain 
low-grade, highly oxygenated coals nearly two-thirds of the oxygen 

a Constam, E. J., and Schlapfer, P., Jour. Gasbel., 1906, pp. 741,774. 



12 


THE VOLATILE MATTER OF COAL. 


appears in the volatile products in union with carbon, and that this 
accounts largely for the difference between the determined heat value 
and that calculated by Dulong’s method. (See pp. 42-44.) 

RELATED INVESTIGATIONS BY OTHERS. 

E. Bornstein'^ has carried out elaborate experiments on the dis¬ 
tillation of German bituminous and brown coals at temperatures up 
to 450° C. He obtained tars with no solid aromatic hydrocarbons 
and gases containing large amounts of CO2 and homologues of 
methane. 

E. J. Constam and E. A. Kolbe^ distilled at high temperatures a 
number of bituminous coals of varying composition and obtained 
from those high in oxygen large amounts of CO2 and CO and corre¬ 
spondingly less amounts of hydrocarbons. 

L. Vignon^^ distilled at 900° C. five coals of varying known oxygen 
content and attempted to establish a ratio between the amount of 
the oxides of carbon and the oxygen in the coal. 

S. W. Parr and C. K. Francis‘S have distilled Illinois coal (4 to 5 
pounds) at 200° to 425° C. for two to three hours in an inert atmos¬ 
phere and obtained from 3 to 4.5 per cent of water of composition, a 
small amount of oil, and 600 to 700 cubic feet per ton of gas high in 
CO2, illuminants, and methane.” Homologues of methane are not 
mentioned in the report of this work, but are probably included 
under '‘methane.” 

A. H. White, F. E. Park, and W. A. Dunkley,^ have studied the low- 
temperature distillation of three typical American coals and its bear¬ 
ing on the manufacture of illuminating gas. They distilled 50 to 75 
grams for six to eight hours at 300° to 500° C. and obtained small 
quantities of liquid and oily distillates with 1,200 to 2,800 cubic feet 
per ton of gas rich in methane and ethane. The following tabulated 
statement of results is given: 

Table 2, —Gas obtained by distillation of three typical American coals. 


Volume and composition of gas. 

Pitts¬ 

burgh, 

Pa. 

Bay 

City, 

Mich. 

Zeigler, 

Ill. 

Volume of gas (cubic feet per pound of coal). 

1.42 

1.15 

16.2 

4.1 

0.63 

13.1 

1.6 

5.8 
13.9 
38.0 
19.5 

7.8 

Average composition of gas: 

CO 2 . 

2.9 

Illuminants. 

2.2 

CO. 

6.2 

5.0 

16.4 

H. 

26.3 

CHi. 

47.0 

37.8 

CsUg . 

13.2 

11.8 

N. 

2.7 

9.1 



aZeltschr.angew. Cheraie, vol. 17, 1904, p. 1520; Jour. Gasbel., vol. 49, 1906, pp. 627, 648, 667; Jour. Soc. 
Chera. Ind., vol. 25,1906, pp. 213, 583. 
t Jour. Gasbel., vol. 51,1908, p. 669. 
cBnll. Soc. chim., 4th ser., vol. 3,1908, p. 109. 

Bull. 24, Univ. Illinois Eng. Exper. Sta., 1908; Trans. Am. Inst. Min. Eng., 1908, p. 1158. 

« Am. Gas Light Jour.; vol. 89, 1908, p. 621. 
















INTEODUCTION. 


13 


The heating power of the solid residue was greater than that of the 
coal, but the coking property was destroyed. The manner and the 
points of temperature measurement are not stated. 

R. T. Chamberlin, of the United States Geological Survey, has made 
a study ® of the gases liberated from coal at ordinary temperature 
and of those evolved from coal dust at somewhat higher temperatures 
(200® to 450® C.). He ascribes the evolution of gas that occurs at 
450® largely to chemical changes in the coal substance rather than to 
liberation of imprisoned gas. The gas at 450® consisted of 60 to 70 
per cent of methane, 12 to 18 per cent of ethane, 5 to 6 per cent of 
heavy hydrocarbons (benzene, ethylene, etc.), and small percentages 
of carbon dioxide, carbon monoxide, and sulphurous gases. Cham¬ 
berlin’s results are applied to an investigation of the causes of mine 
explosions and to the method of accumulation of gas in mines. At 
temperatures below 350® he obtained only very slight percentages of 
ethane in the gas, and concludes that in the imprisoned gases of the 
coals studied (Pennsylvania and West Virginia) ethane is not present 
to any appreciable extent.^ 

EXPERIMENTAL PLAN OF PRESENT INVESTIGATION. 

It has been the plan in the present investigation to extend such 
studies as those described above to several types of American coals 
and to a greater variety of experimental conditions of such kind as 
to indicate the behavior of these coal types in their industrial appli¬ 
cations. It has been borne in mind throughout that industrial 
conditions can scarcely be duplicated in the laboratory, and that 
any selected set of laboratory conditions (of temperature and of 
quantity, for example) must be considered as corresponding to merely 
a part of the varied conditions that may exist simultaneously in an 
industrial practice. The laboratory method, however, permits more 
exact measurements and presents the further advantage that a 
few definite and controllable conditions can be selected from among 
the many indefinite ones of industrial practice, and their effect 
determined with more certainty. It is not claimed that the experi¬ 
mental data of this investigation show absolute industrial yields 
either in quantity or in composition of products, but it is held that 
they afford a comparison of various coals under fixed conditions, 
and also that they justify conclusions as to the probable industrial 
behavior of the different coals, in furnace, coke oven, or producer. 


a Notes on explosive mine gases and dusts: U. S. Geol. Survey Bull. No. 383,1909. 
t After the publication of the first edition of Bulletin 1, Bureau of Mines, there appeared in the Journal 
of the Chemical Society (London), vol. 97, p. 1917, and vol. 99, p. 649, two articles by M. J. Burgess and 

R. V. Wheeler on “ The Volatile Constituents of Coal/' describing an investigation similar to that described 
here. For the results of still later Investigations, see “The Coking of Coal at Low Temperatures,” by 

S. W. Parr and H. L. Olin. Bull. 60, Univ. Illinois Eng. Exper. Sta., 1912. 



14 


THE VOLATILE MATTER OF COAL. 


For comparing coals as to the composition and the rate of forma¬ 
tion of their volatile products at a number of given temperatures, 
10 -gram samples of air-dried powdered coal were heated in an inert 
atmosphere in a platinum retort. For comparing coals as to their 
yields of by-products of coking, under one given set of conditions 
approximating those of industrial practice, tests were made on 
400-gram samples of crushed coal as received, heated in a cast-iron 
retort. Direct weighing of tar and of water of composition and the 
determination of ammonia were capable of greater accuracy in the 
400-gram tests than in the 10-gram tests. Nine different coal types 
were used, ranging from a low-grade subbituminous coal from Wyo¬ 
ming to the high-grade Connellsville and Pocahontas coals of the 
Appalachian region. 

METHODS. 

COLLECTION AND PREPARATION OF SAMPLES. 

The samples of coal used in these investigations were with one 
exception mine samples collected by representatives of the United 
States Geological Survey in the manner prescribed for the work of the 
fuel-testing plant.® The one exception was coal No. 23 from a mine 
near Harrisburg, Saline County, Ill., this sample being a car sample of 
screened coal (2-inch to 3-inch size) taken by a representative of the 
Illinois State Geological Survey from a car at the mine, one day after 
it had been mined. 

Samples of about 100 pounds each, representing the entire seam as 
mined, were shipped to the laboratory in canvas bags or (in case of 
coals particularly subject to deterioration from exposure) in tightly 
closed kegs or barrels. 

At the laboratory the entire sample was crushed to J-inch size and 
a portion of 8 to 10 pounds was taken by quartering for air drying. 
From this air-dried portion a 500-gram sample was taken by quar¬ 
tering, pulverized to 60-mesh size in the closed ball mill, and bottled 
in a ‘‘lightning” fruit jar for analysis. The bulk of the original 
sample was placed in a galvanized ash can having a tightly fitting 
cover, and the portion of the air-dried sample not pulverized was 
placed in a tin milk can with a tight cover sealed with tape. The 
time that elapsed between mining the coal and placing it in covered 
containers varied from three to five weel^s; during this time there 
was undoubtedly some loss in mine moisture and possibly slight changes 
in the coal substance due to oxidation. The subbituminous coals, 
however, which are high in moisture and more subject to change, 
were kept in tightly closed kegs and probably changed very little. 


a Bull. U. S. Geol. Survey No. 290, 1906, p. 17. 



METHODS. 


15 


The proximate analyses and sulphur, nitrogen, and calorimetric 
determinations were made on the air-dried powdered samples accord¬ 
ing to the methods of the fuel-testing plant.® 

TESTS IN IRON RETORT. 

APPARATUS. 

For the purpose of comparing coals in respect to their yields of 
by-products of coking as well as the composition of their volatile 
products, a cast-iron retort holding somewhat less than a pound of 
coal was used, together with apparatus as illustrated in Plate I, A. 

The bottles a, b, c, and d contain dilute sulphuric acid; the tower 
e and condenser / contain glass beads over which water flows from 
the funnel g] the upper portion of f contaiiLs absorbent cotton to 
collect the last traces of tar. It was found by placing two drops of 
normal acid in d, with a little cochineal as indicator, that no ammonia 
passed through the acid in c. The bottle h contains 30 per cent 
potassium hydroxide solution and the tower i holds glass beads wet 
with the same solution from funnel j. The gages Ic indicate the gas 
pressure at the beginning and end of the train. Temperatures in the 
furnace and inside the iron retort were read by means of thermo¬ 
couples connected through a cold junction bath (Z) and switch to 
the millivoltmeter (m). 

Figure 1 shows a vertical section through the furnace viewed from 
the side. This furnace was designed and constructed on the plan of 
those used by A. L. Day in the geophysical laboratory of the Carnegie 
Institution, Washington, D. C.^ The outer cylindrical jacket (A) is 
of ordinary fire clay and the inner one (C) of “magnesite,^’ a highly 
refractory material composed chiefly of magnesium oxide. The inner 
cylinder rests upon small fire-clay blocks, and the space (B) between 
the two cylinders is filled with light calcined magnesia. For con¬ 
venience in winding the heating coils, the inner cylinder is in two 
sections placed end to end. The heating coils (D) are of pure nickel 
wire. No. 13 Brown & Sharpe gage, and are cemented to the inside of 
the inner cylinders by means of “magnesite"’ powder wet with water 
and a little gum tragacanth. The strands of wire are about 2 milli¬ 
meters apart. For winding the coils a cylindrical arbor of hard wood 
is used, which is slightly smaller than the inside diameter of the furnace 
and is made up of wedge-shaped sections, so as to be collapsible and 
readily removed. The arbor, after being covered with paper, is 
wound with the wire, coated with cement, and placed in the furnace 
cylinder, and the annular space is packed with cement. After drying 
thoroughly, the arbor is removed and a final surface layer of cement 
is coated over the coils. 


a Prof. Paper U. S. Geol. Survey No. 48, 1906, pp. 178-190. 

6 Day, A. L., and Allen, E. T., Am. Jour. Sci., 4th ser., vol. 19,1905, p. 93. 




16 


THE VOLATILE MATTEK OF COAL. 


A furnace made thus with nickel wire stands from 50 to 75 heats 
at 1,100° C. without renewal of the coils. The cement covering of 
the coils must, however, be kept intact by frequent patching to 
insure long life of the wire. A direct current of 220 volts was used, 
the strength varying from 18 to 25 amperes according to the varia¬ 
tion of the resistance with the temperature. 

Figure 1 shows also a vertical section of the iron retort viewed from 
the side. When the inside thermocouple is used, the coke is con¬ 
veniently added through the delivery pipe after the pipe is screwed in 



SECTION OF FURNACE 

Figure 1.—Section of iron retort and section of large electric furnace. 


place. The retort burns away on the surface and can be used for only 
6 to 8 heats at 1,100°. 

It was found impracticable to have the threaded joint of the retort 
inside the furnace and maintain it gas tight or to constrict the 
neck of the retort near the joint because of difficulty in removing the 
coke. If the threads are well made and kept lubricated with graphite 
there is no difficulty in keeping the joint gas tight. The walls of the 
retort were made heavy (one-half inch) so as to withstand better the 
scaling effect of the high heat. The conditions as to rate of heating 





















































METHODS. 


17 


were therefore somewhat different from those of a coke oven or gas 
retort where the coal is charged directly into the heated chamber. 
The difference, however, is due more to loss by radiation through the 
large exposed surface of the retort outside of the furnace than to the 
presence of the iron wall between the coal and the furnace. The iron 
wall of the retort transmits heat to the coal rapidly, being a better 
conductor of heat than the layer of partly coked coal which forms 
next to the walls of a coke oven when the charge is introduced. The 
temperature less than 4 inches from the wall of a retort coke oven has 
been found to remain below 200° C. for five hours after charging. 

The radiation, however, from the front and neck of the iron retort 
lowers the temperature of those portions to such a degree that tar 
vapors and heavy hydrocarbon gases pass through with less break¬ 
ing down than in coke ovens or gas retorts; consequently the yields 
of tar and heavy paraffin hydrocarbons are greater in the laboratory 
tests than in commercial practice. The front part of the retort is 
filled with coke, in pieces of about J-inch size, for the purpose of 
preventing the crowding forward of coal and tar. This coke does 
not become hotter than 600° C., on account of the cooling effect of 
radiation on the front of the furnace and retort. It is important to 
have the coal occupy the same space in the retort and be in the same 
relative position in the furnace in all tests, for the gas yield is 
materially influenced by these conditions. 

The thermocouples and millivoltmeter used were standardized at 
the beginning of the investigations by the Bureau of Standards, 
Washington, D! C., and found to be correct within 5° C. at tempera¬ 
tures between 400° and 1,600° C., the cold junctions being at 25° C. 
They were standardized also after the completion of these investiga¬ 
tions, at the physical laboratory of the Bureau of Mines, by means 
of the melting points of pure zinc and pure copper, and were again 
found correct within the limit mentioned. 

The gas meter used {p, PI. I, A) was Goodwin’s experimental gas 
meter of 0.1 cubic foot capacity per revolution, furnished by the 
American Meter Company. The correct water level in the meter was 
established by aspirating about 0.5 cubic foot of air through the 
meter and determining its volume by the weight of water displaced 
in the aspirator bottles. For collecting the gas a 55-gallon barrel 
(r, PI. I, A) which had been rendered gas tight by a coat of shellac 
was used. The gas was collected by displacement of water previously 
saturated with gas. 

OPERATION. 

The furnace having been brought to a temperature of 1,070° to 
1,080° G. at its center, the retort charged with 400 grams of coal and 
100 grams of coke, as shown in figure 1, and the train of by-product 
90147°—Bull. 1—13-3 


18 


THE VOLATILE MATTER OF COAL. 


apparatus made ready, the retort was quickly placed in the furnace 
and the fire-clay doors were replaced. Connection was then made 
with bottle a (see PI. I, A) and temperature readings were taken at 
intervals of five minutes. The temperature of the furnace is lowered 
to 720° to 750° by the introduction of the retort, but after about five 
minutes begins to rise again at the rate of 5° to 6° per minute. Gas 
begins to be evolved about five minutes after the retort is placed 
in the furnace. Bottles a, h, c, and d, and the tower e were weighed 
with their connections and contents before and after the test. The gain 
in weight, together with a correction for water evaporated (based on 
the volume of gas and its temperature), was taken as tar, water, and 
ammonia. These weighings were made with an accuracy of 0.2 
gram (0.05 per cent on the coal sample used). An approximate sepa¬ 
ration of tar and water was made, but the method was necessarily 
crude and no claim is made for accuracy nearer than 1 per cent. 
After all the tar and liquor from bottles a, h, c, and d were col¬ 
lected the bulk of the aqueous liquor was decanted and the tar 
washed thoroughly with a measured quantity of water in six or eight 
successive portions. The water from tower e was used as part of the 
wash water. These washings were added to the decanted liquor and 
the whole was measured. The tar was then distilled to 180° C. and 
the water in the distillate was measured. The total measured amount 
of water less the wash water added was subtracted from the total tar 
and water weighed, and the difference was taken as dry tar. For 
ammonia determination the aqueous liquor and washings were made 
up to definite volume and aliquot portions were distilled with alkali, 
the ammonia was received in excess of normal H2SO4 and the surplus 
acid was titrated with normal NaOH and cochineal. The degree of 
washing necessary to remove all ammonia from the tar was deter¬ 
mined by analyzing successive washings, and an excess over this 
amount was used. 

The water in funnel g (100 cubic centimeters) and the KOH solu¬ 
tion in funnel j were admitted to the towers below in small successive 
portions during the test. The KOH liquor was collected after the 
test, made up to definite volume and its content of CO2 determined 
by evolution with acid and absorption in weighed potash bulbs 
according to Hillebrand’s method.® A blank was run on the original 
KOH solution and correction made accordingly. 

HjS was determined in the KOH liquor by acidifying a small por¬ 
tion diluted to 400 or 500 cubic centimeters and titrating with deci- 
normal iodine solution. 

The gas was measured by the meter, the collecting reservoir being 
used merely for the purpose of obtaining a true average sample. 

oHillebrand, W. F., The analysis of silicate and carbonate rocks: Bull. U. S. Qeol. Survey No. 305, 
1906, p. 150. 



BUREAU OF MINES 


BULLETIN NO, 1 PLATE I 



A. APPARATUS USED IN DISTILLING 400-GRAM SAMPLES OF COAL IN IRON RETORT. 



n. APPARATUS USED IN DISTILLING 10-GRAM SAMPLES OF COAL IN PLATINUM RETORT. 





















































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METHODS. 


19 


The air in the apparatus (about 0.2 cubic foot) at the beginning of 
a test was allowed to mix with the gas, and the average analysis was 
corrected to an air-free basis, all the oxygen present being assumed 
as due to air. The meter reading, however, represents the true 
yield of gas, for the same volume remains in the apparatus after the 
test as before. There is a small error in obtaining the average analysis, 
as the gas remaining in the apparatus at the close is not of the 
average composition. Successive samples of gas were taken during 
the progress of the test, through a T connection between the meter 
and reservoir. 

The coke was removed from the retort and weighed to 0.5 gram. 
A small amount of tar (less than 0.5 per cent) remains on the walls 
of the delivery pipe. 

By means of the gages (k, PI. I, A) a suction of about 2 inches of 
water was maintained beyond the meter and the gas pressure in 
bottle h was observed. This pressure varied from 8. to 25 inches of 
water and served incidentally to indicate leaks in the apparatus. 
The test was continued until gas practically ceased to be evolved— 
that is, until less than 0.01 cubic foot per minute was produced. 
The time required to reach this point varied somewhat with the 
coal but was usually about one hour. The inside temperature (at 
the surface of the coal) usually attained 800° C. The furnace 
temperature was not allowed to rise above 1,100° C. 

TESTS IN PLATINUM RETORT. 

APPARATUS. 

For the purpose of comparing coals in respect to the quantity and 
composition of their volatile products at different temperatures, a 
small platinum retort having a capacity of about 150 cubic centi¬ 
meters was used, the retort being provided with a platinum cover, 
delivery tube, and inlet tube. The arrangement of the apparatus is 
illustrated in Plate I, B, and the detail of furnace and retort in 
figure 2. 

The retort (ct, PI. I, B) was connected by means of heavy rubber 
tubing protected by asbestos to a 6-inch U tube and 6-inch straight 
tube, both tubes being filled with absorbent cotton and inclosed in 
air baths (6) maintained at 110° C. Following the tubes containing 
cotton were two 5-inch U tubes containing CaCl2 ifi and d), a pro¬ 
tecting tube containing the same (e), and finally a pair of 5-liter 
aspirator bottles (/) for collecting gas. The water in the bottles had 
been previously saturated with gas. One bottle was graduated for 
measurement of the gas and contained a thermometer. The cotton 
tubes were previously dried in a current of air at 110° C. Connected 
to the inlet tube of the retort was a 20-inch straight tube containing 


20 


THE VOLATILE MATTER OF COAL. 


CaClg (h) and a 12-inch tube containing soda lime (g) for drying and 
purifying the air or nitrogen entering the retort. Nitrogen for these 
tests was prepared by drawing a slow current of air first through 



alkaline pyrogallol solution in two wash bottles and then over heated 
copper gauze in a combustion tube. The nitrogen prepared in this 
way contained from 0.2 to 0.4 per cent of oxygen. 





















































































METHODS. 


21 


As shown in figure 2, the small vertical electric furnace was 
similar in construction to the large furnace used in the 1-pound 
tests, the dimensions differing, however, as indicated. The retort 
has a ground joint at A, which can be kept gas tight if shaped by a 
hard-wood form and polished with fine emery cloth before each test. 
The inner end of the platinum inlet tube is 10 millimeters above 
the bottom of the retort and the junction of the inside thermocouple 
(B) 5 millimeters above the bottom. It is important that the position 
of this thermocouple be kept the same in parallel tests, for a slight 
difference in its elevation materially affects the temperature reading. 
The wires of the couple were insulated by fine porcelain tubes, but 
the junction itself was bare. At C the wires of the thermocouple 
passed through a cork stopper and a coating of sealing wax; D is the 
inlet for dry nitrogen or air. The retort was placed in the furnace 
always at the same height and the temperature of the furnace was 
taken at the level of the bottom of the retort next the furnace wall. 

In figure 2 is shown also the air bath for heating the tubes con¬ 
taining cotton. The inner cylindrical chamber (A) was of tin and 
was surrounded by a jacket of sheet asbestos (B). The cover (C) was 
of asbestos. The ring burner (D) encircles the block (E) which 
supports the bath. 

OPERATION. 

It was found advisable, on account of the necessity of aspiration 
in the tar and water determinations, to run the tests for gas separately. 
For the gas tests, therefore, the platinum retort was connected 
directly to the gas-collecting bottle, the tar and water being disre¬ 
garded. The furnace temperature having attained constancy at the 
desired point, 10 grams of air-dried powdered coal was placed in the 
retort, the joint was made tight, and the air was displaced by nitrogen, 
a volume of nitrogen being aspirated equal to three times the capacity 
of the retort. This amount of aspiration was found to reduce the 
oxygen to less than 1.0 per cent in the atmosphere of the retort. 
Connection was then made to the gas-collecting bottle, the retort 
lowered into the furnace, and the time noted. Temperature read¬ 
ings inside and outside of the retort were taken at one-minute inter¬ 
vals, and when the distillation had proceeded to the point desired the 
retort was quickly removed and cooled by immersion in water.® A 
thorough mixture of the gas and nitrogen was obtained by passing 
them back and forth three times from the gas-collecting bottle through 
the retort to the nitrogen reservoir. The gas was measured, its tem¬ 
perature taken, and an average sample analyzed. Although a certain 
proportion of the nitrogen present is undoubtedly produced by the 
coal, all analyses were calculated to a nitrogen-free basis to eliminate 
the effect of dilution with the added nitrogen. 

a In some of these experiments the distillation was carried to an end, that is, imtil no more gas was 
evolved; in others it was continued for a limited period fixed either independently of other conditions 
or, in another series, by the attainment of a certain temperature in the coal. Because of radiation, the maxi¬ 
mum temperature reached in the coal was 75 to 120° C. below that of the furnace. 



22 


THE VOLATILE MATTER OF COAL. 


In the tar and water determinations the gas was disregarded. 
After the retort was filled with nitrogen, the drying train was con¬ 
nected and the retort lowered into the furnace, the pinchcock at D 
(fig. 2) being closed. After having been heated for the desired length 
of time the retort was removed and cooled as before and 4 liters 
of dry air was drawn through it. During the aspirating process the 
platinum delivery tube was warmed with a small flame to drive 
out all water. The gain in weight of the retort cap and delivery tube 
was determined and, together with the gain in the cotton tubes, plus 
a correction for light oils, was taken as tar. The gain in the calcium 
chloride tubes less the correction for light oils was taken as water. 
In tests at 900 ° C. and higher it was necessary to use two cotton tubes 
in order to retain all the tar, though only one is shown in figure 2. 
As oils volatile below 110° C. are carried over into the calcium chlo¬ 
ride tubes and weighed as water, a correction of 5 per cent of the tar 
weighed is applied, this being based on the maximum percentage of 
light oil in coke-oven tar according to Lunge.® The tar and water 
separation is therefore approximate only, and no claim is made for 
greater accuracy in the separation than 1 per cent on the coal. 

METHODS OF GAS ANALYSIS. 

In general, the Hempel methods of gas analysis were used through¬ 
out the investigation, although certain modifications were used that 
increased the accuracy. 

CARBON DIOXIDE, OXYGEN, ILLUMINANTS, AND CARBON MONOXIDE. 

For the determination of COj a 30 per cent solution of commercial 
NaOH, for oxygen alkaline pyrogallol solution containing 100 grams 
pyrogallol and 150 grams NaOH per liter, for illuminants fuming 
sulphuric acid (20 per cent SOg), and for CO ammoniacal cuprous 
chloride solution according to Winkler’s formula ^ (250 grams NH4CI 
and 200 grams CugClg in 1 liter, mixed just before use with one-third 
volume aqua ammonia of specific gravity 0 . 91 ) was used. A record 
of the use of each pipette was kept by noting upon it the volume of 
gas absorbed during each determination. For the determination of 
more than 12 per cent of CO three pipettes were used successively. 

BENZENE. 

For the determination of benzene a large amount of experimental 
work was done in testing two methods, neither of which proved 
entirely satisfactory. The method of D. A. Morton,'^ using sulphu¬ 
ric acid of specific gravity 1 . 84 , was found to give approximately com- 

o Lunge, G., Coal tar and ammonia, 3d ed., p. 81. 
b Winkler, C., Technische Gas Analyse, 2d German ed., p. 77. 
c Jour. Am. Chem. Soc., vol. 28,1906, p. 1728. 

<* See Addenda, p. 66. 



METHODS. 


23 


plete absorption of the benzene from benzene and air mixtures in three 
minutes’ shaking; but for coal gas containing various other hydrocar¬ 
bons as well as benzene the method did not yield concordant results on 
the same sample and therefore was discarded. The method of L. M. 
Dennis and E. S. McCarthy,® using an ammoniacal solution of ammon¬ 
ium nickel cyanide, was not found satisfactory. The absorption 
proved incomplete from known mixtures of benzene and coal gas in 
two minutes’ treatment carried out as directed by the authors, and 
concordant results on the same sample could not be obtained. 

In giving results of the gas analyses of the present investigation, 
therefore, no attempt has been made to differentiate the constituents 
absorbed by fuming sulphuric acid, designated as illuminants. 

HYDROGEN. 

In most of the tests hydrogen was determined separately by means 
of palladium asbestos, as recommended by F. C. Phillips,* the method 
being that of Winkler.'^ Palladium black was precipitated upon 
acid-washed ignited asbestos by the action of alkaline sodium for¬ 
mate on palladium chloride solution, the product being then washed, 
dried, and ignited at a moderate red heat. A mixture of the gas 
residue (after removal of CO) with air, equivalent to an oxygen- 
hydrogen ratio of at least 2:1 by volume, was passed slowly over the 
palladium in a small U tube maintained at 50° to 70° C. by a water 
bath. After this mixture was passed three times through the tube 
the contraction was complete and the gas was cooled by passing once 
through the tube immersed in water at room temperature. A water- 
jacketed burette was used for this determination, and a Hempel 
pipette containing distilled water was used for receiving the gas after 
passage through the palladium tube. The palladium asbestos must 
be dried thoroughly after each combustion of hydrogen and must be 
carefully protected from contamination with acid fumes. According 
to Phillips hydrogen is completely burned under these conditions and 
hydrocarbons are not affected. The writers have verified this state¬ 
ment by tests with pure electrolytic hydrogen and also with samples 
of natural gas, testing for the formation of CO 2 . 

METHANE AND ITS HOMOLOGUES. 

For the determination of paraffin hydrocarbons of the general 
formula CnH 2 n +2 (methane, ethane, etc.), Winkler’s method of slow 
combustion by a heated platinum spiral,'^ as modified by L. M. 
Dennis and C. G. Hopkins,^ was used. 

o Jour. Am. Chem. Soc., vol. 30,1908, p. 233. 
fr Am. Chem. Jour., vol. 16,1893, pp. 164-168. 
c Winkler, C., Technische Gas Analyse, 2d German ed., pp. 145-150. 
d Idem, pp. 155-157. 

« Hempel, W., Gas analysis (trans. of 3d German ed.), p. 138. 



24 


THE VOLATILE MATTEK OF COAL. 


The combustion pipette was of glass. The spiral was made of about 
10 inches of No. 24 platinum wire and the ends of the spiral were 
welded to somewhat larger platinum wires which, insulated by glass 
tubes, passed downward through the rubber stopper and were con¬ 
nected to the source of the electric current. It was found necessary 
to avoid the use of any baser metal than platinum in the fittings 
of the pipette, as a considerable error is introduced thus by oxidation 
of the metal. 

The total contraction and CO 2 produced by the combustion hav¬ 
ing been determined, and the contraction due to hydrogen separately 
determined by palladium and subtracted, the result indicated the 
contraction and the CO 2 due to the burning of methane and its homo- 
logues. As shown by E. H. Earnshaw,® the total volume of hydro¬ 
carbons of the type CnH 2 n +2 and also the value of n could then be 
calculated, showing the average composition of the hydrocarbon 
mixture. For a given amount of contraction and CO 2 the total vol¬ 
ume of CnH 2 n+ 2 the Same, regardless of the relative percentages of 
CH 4 , C 2 H 6 , CgHg, etc. Thus: 


= (n) COj + (n + 1 ) H^O. 


If V = volume of CnH 2 n +2 

( 1 ) Contraction = ^ V + ^ _nV = 


(2) C02 = Vn. 

By combining (1) and (2) V = ^ contraction - CO, 

o 


and 


n = 


CO, 

V 


Without further data it is impossible to determine the relative 
percentage of any one of the hydrocarbons when more than two are 
present. 

If we assume, however, that only methane (CH^) and ethane 
(C 2 He) are present, and find, for example, 1.25 for the value of n and 
24 per cent for the total CnH 2 n+ 2 , then ethane is 25 per cent of the 
total, or 6 per cent; if n is found to be 1.33 and the total 24 per cent, 
then ethane is 8 per cent. 

a Jour. Franklin Inst., September, 1898. 

Note.—T he method of determining methane and hydrogen in gas mixtures by binning or exploding 
with air or oxygen, and not separately determining the hydrogen,introduces a serious error when ethane 
or higher hydrocarbons are present. This method, under the last-mentioned conditions, indicates a per¬ 
centage of hydrocarbons that is greater and a percentage of hydrogen that is less than the true percentage. 







SUMMARY OF RESULTS. 


25 


SUMMARY AND INTERPRETATION OF RESULTS. 

COALS TESTED. 

The following tables show the source and composition of the coals 
used for the tests herein described: 

Table 3. —Source of coal samples used in tests. 


Labo¬ 

ratory 

No.o 


State. 


Post-office. 


Seam or bed. 


Mine. 


Date 

collected. 


1 Illinois. 

3 Pennsylvania 


10 

11 

16 


West Virginia. 

Wyoming_ 

Virginia. 


18 


Wyoming 


23 

25 

46 


Illinois... 

Utah. 

Wyoming 


Zeigler, Franklin County.. 
Connellsvllle, Fayette 
County. 

Page, Fayette County. 

Dietz, Sheridan County b .. 
Pocahontas, Tazewell 
County. 

Diamondville, Uinta 
County. 

Harrisburg, Saline County 
Castle Gate, Carbon County 
Near Kemmerer, Uinta 
County. 


No. 7_ 

Pittsburg 

No. 2 gas. 

No.'sV.V' 


Zeigler.... 
Lelsenring 
No. 1. 
Ansted.... 

No. 1. 

Baby. 


No. 1 


No. 5. 

Wiilow Creek 


No. 8 


June 23,1907 
June 20,1907 

Oct. 7,1907 
Sept. 24,1907 
Nov. 23,1907 

Dec. 9,1907 

Jan. 30,1908 
Mar., 1908 
Mar., 1909 


o Special laboratory number not corresponding to those of the general laboratory of the fuel-testing plant. 
b Subbitumlnous. 


Table 4. —Analyses of coals tested. 


Laboratory No. 

1 . 

3. 

10 . 

11. 

16. 

18. 

23. 

25. 

46. 

Bulk sample (100 pounds). 










Air-drying loss. 

1.63 

0.10 

0.69 

14.63 

0.81 

2.30 

5.21 

0.56 

1.64 

Analysis of air-dried sample: 











/ 7.67 

1.10 

.87 

11.45 

.35 

2.64 

1.96 

2.30 

2.17 

Moisture a . 

1 7 40 

1 09 

Qfi 

10 83 

59 

3 48 




Volatile matter. 

30.38 

30.67 

32.46 

6 35.74 

20.93 

42.23 

32.05 

40.24 

34.01 

Fixed carbon. 

54.32 

60.35 

61.66 

47.74 

75.51 

50.65 

56.75 

51.38 

58.37 

Ash. 

7.63 

7.88 

5.01 

5.07 

3.21 

4.48 

9.24 

6.08 

5.45 

Computed to “as received” basis: 










Moisture o. 

9.19 

1.18 

1.55 

/ 24.40 
\ 21.96 

} 1.16 

4.88 

7.07 

2.85 

3.74 

Volatile matter. 

29.89 

30.64 

32.22 

30.52 

20.76 

41.25 

1 ^. 37 

40.04 

33.46 

Fixed carbon. 

53. 41 

60.31 

61.26 

40.75 

74.90 

49.49 

53.80 

51.06 

57.44 

Ash. 

7.51 

7.87 

4.97 

4.33 

3.18 

4.38 

8.76 

6.05 

5.36 

Sulphur. 




.38 

.61 

.41 

1.48 

.42 

.91 

Nitrogen. 




1.15 

1.07 

.97 

1.27 

1.16 












1-pound mine sample correspond- 










ing to above. 










Pan Mn 

3,249 

3,245 

3,625 

- (0 






Analysis on basis of sample as 






received: 











11.82 

3.24 

2.65 

12.28 







27.66 

27.13 

29.69 

36.96 






TTWoH narHnn 

55.10 

62.52 

63.50 

45.88 







5.42 

7.11 

4.16 

4.88 







.46 

.95 

1.29 

.45 







67.87 

78.00 


60.44 







5.44 

5.24 


5.36 







1.34 

1.23 


1.32 







19. 47 

7.47 


27.55 






A'AJt .. 

6,645 

7,733 

8,104 

5,774 







11,961 

13^919 

14,587 

10,393 






X>1 i l/ilCl IXlCVi LlLli to 








o Second determinations given were made on same samples twelve to eighteen months later. 
b Determined by modified method; Somermeier, E. E., Jour. Am. Chem. Soc., vol. 28,1906, p. 1002. 
c Air-dried No. 11, same as above. 

90147°—Bull. 1—13-4 
































































































26 


THE VOLATILE MATTER OF COAL. 


TESTS OF COAL IN IRON RETORT FOR BY-PRODUCTS OF COKING. 

SUMMARIES OF TESTS. 

In order to determine the adaptability of certain western coals to 
the production of gas, tar, and ammonia as by-products of coke 
making or of gas manufacture, one southern Illinois coal, two Wyo¬ 
ming coals, and one Utah coal were tested in the iron retort; and 
for standards of comparison several tests were made on the well- 
known Connellsville and Pocahontas coals of the Appalachian 
region. A few experiments also were carried out with the Con¬ 
nellsville coal for the study of the effect of moisture in the coal on 
the ammonia yield. Tables 5, 6, and 7 give summaries of the 
average results. Detailed data of the individual tests will be found 
on pages 45 to 47. 

Table 5. —Results of hy-jproduct tests. 

[See p. 25 for analyses and description of coals.] 


Laboratory No. 

16. 

3. 

23. 

11. 

11 (air 
dried). 

25. 

46. 

Number of tests averaged. 

2 

6 

2 

4 

2 

2 

2 

Coke.per cent.. 

79.1 

71.4 

63.1 

44.7 

53.0 

58.6 

63.9 

Tar.do_ 

7.2 

11.3 

11.9 

7.1 

5.5 

12.3 

10.3 

Water.do— 

1.3 

4.9 

10.7 

27.5 

19.0 

11.8 

10.0 

Anunonla.pounds of sulphate per ton.. 

12.9 

23.8 

25.3 

27.2 

26.7 

26.3 

26.3 

COj.per cent.. 

.44 

.72 

1.20 

8.14 

8.41 

3.13 

2.13 

HjS.do— 

.07 

.25 

.46 

.08 

.11 

.24 

.30 

Gas.cubic feet per ton a .. 

9,700 

8,140 

8,400 

7,830 

8,170 

7,620 

7,940 

Con^osition of gas: 5 

Illuminants. 

1.4 

3.2 

3.0 

2.2 

2.6 

5.7 

5.5 

CO. 

3.2 

5.1 

7.4 

19.5 

21.4 

14.9 

12.3 

CH<, CjH«, etc. 

26.4 

27.8 

C26.3 

18.1 

C22.6 

27.2 

25.4 

H. 

67.8 

61.0 

C56.8 

54.0 

C49.3 

47.8 

53.1 

N. 

1.2 

2.9 

6.5 

6.2 

4.1 

4.4 

3.7 

Value of n in CnH2n+j. 

(0 

1.27 

(<=) 

1.18 


1.32 

1.29 

Total volatile products (without moisture).... 

19.7 

27.4 

29.8 

33.3 

35.5 

38.5 

32.4 

Water of constitution. 

.1 

3.7 

3.6 

5.5 

7.5 

8.9 

6.3 

Inert volatiie matter d. 

.7 

4.7 

5.1 

14.0 

16.3 

12.4 

8.8 


o Calculated to dry basis at 0° C. and 760 millimeters pressure, free of air and COj. 
b Calculated to CO2 and O free basis. 

c Hydrogen not determined separately by palladium but calculated from combustion; CH4 probably 
high and H low. 

d Sum of CO2, ammonia, and water of constitution. 

The conditions in all the above tests were approximately those 
described under ‘^Methods” (pp. 15-19). 

The western coals give larger ammonia yields under the laboratory 
conditions than the Connellsville coal. The bituminous coals. No. 25 
(Utah) and No. 46 (Wyoming), yield a gas of good quality, nearly 
twice as high in percentage of illuminants as that from the Connells¬ 
ville coal. The yield is somewhat smaller than the Connellsville yield, 
however, when the gas is freed of CO 2 . Coal No. 23, from Harrisburg, 
Ill., gives a somewhat higher yield of gas than the Connellsville coal 
and the gas is of similar composition. All these coals, except No. 11, 
produce coke in the laboratory test, but this result can not be relied 
on even as an indication of industrial coking possibilities. 





























SUMMARY OF RESULTS. 


27 


The subbituminous Wyoming coal, No. 11, yields large quantities 
of gas very high in CO 2 and CO. Comparative tests on this coal as 
received and air-dried are shown in the above table. In order to be 
fairly comparable, however, they must be computed to an equivalent 
basis, that of the moisture-free material, and the results expressed in 
percentages of dry coal, as follows: 


Table 6 .— Tests of coal from Sheridan field, Wyoming (laboratory No. 11), computed to 

dry basis. 



Coal dis¬ 
tilled as 
received. 

Coal dis¬ 
tilled In 
air-dried 
state. 

Water.do_ 

Ammonia.pounds sulphate per ton.. 

COj.per cent. 

Gas at 0° C. and 760 mm. pressure, free of COj and air, and dry .. .cubic feet per ton.. 

Wate»- of constitution.per cent.. 

Inert volatile matter.do_ 

57.3 

9.1 

35.3 
35.0 

10.4 
10,020 

7.1 
18.0 

59.9 

6.2 

21.5 

30.2 

9.6 

9,250 

8.5 

18.4 


The results as thus expressed show that the absolute quantities of 
products to be obtained from the coal, either as mined or partly dried, 
amount to the above-stated percentages of the dry material present. 
The ammonia yield on the basis of dry material is greater from the 
moist coal than from the air-dried coal; on the same basis also the 
CO 2 and CO are slightly greater from the moist coal, but not so much 
greater as to lead to the conclusion that any considerable amount of 
the large CO 2 and CO production is to be ascribed to the action of 
water vapor on carbon. 

EFFECT OF MOISTURE IN COAL ON AMMONIA YIELD. 

In order to test further the influence of moisture on ammonia yield 
a few tests were run on Connellsville coal moistened so as to contain 
9.6 per cent of water, and on the coal as received, with 1.2 per cent of 
water, under conditions otherwise as nearly the same as possible. 














28 


THE VOLATILE MATTER OF COAL. 


Table 7. —Comparative by-product tests of dry and wet coal. 


[Coal No. 3, with 1.2 and 9.6 per cent of moisture.] 



Percentages of coal 
as used. 

Percentages of 
moisture-free coal. 

Distilled 

dry. 

Distilled 

wet. 

Distilled 

dry. 

Distilled 

wet. 

Number of tests averaged. 

2 

71.4 

10.2 

5.9 

25.0 

7,900 

1.8 

2.7 

5.0 

29.1 

58.7 

2.7 

1.28 

2 

66.6 

9.2 

13.3 

24.3 
6,640 

1.8 

2.8 

5.1 

33.3 
55.0 

2.0 

1.17 

2 

72.3 

10.3 
6.0 

25.3 
8,000 

2 

73.7 
10.2 

14.7 
26.9 

7,350 

Coke.per cent.. 

Water.do_ 

Ammonia.IX)unds of sulphate per ton.. 

GasatO°C. and 760 millimeters pressure, dry., cubic feet per ton.. 
Com^sition of gas: 

Illuminants. 



CO. 



CH4 j CjHsy 6tc... 



H. 



N. 



Value of n in CnHjn4-2. 







On the basis of dry material, the ammonia yield seems to be 
greater again with the wet coal. The gas yield is lower with the wet 
coal, but in composition the gas is somewha't richer in hydrocarbons. 

VARIATION IN GAS COMPOSITION DURING TEST. 

The analyses of gas samples taken successively during the progress 
of the 400-gram by-product tests show the familiar increase of hydro¬ 
gen and decrease of hydrocarbons as the carbonization proceeds. The 
detailed analyses are given on pages 46 to 47. It is of interest to 
note that samples taken early in the test (after the lapse of 20 to 25 
per cent of the coking time) contain in the high-grade coals 50 to 55 
per cent of methane and its homologues and that the proportion of 
ethane and higher homologues is considerably greater in the early 
samples. The early sample from Pocahontas coal is not only rich in 
hydrocarbons but contains also a large percentage of hydrogen (40 
to 45 per cent), wherein it differs from the other coal types. 

INERT VOLATILE MATTER. 

In the tabulated results (Table 5, p. 26) are given percentages of 
inert volatile matter based on the experimental measurement of water 
of constitution, COj, and ammonia. It will be seen that this inert 
material varies from 4 per cent of the total volatile in Pocahontas 
coal to 42 per cent in the subbituminous coal of the Sheridan field, 
Wyoming. The results of tests on 10-gram samples of coal given on 
pages 38-40 and 49-54 are similar to those above noted. These 
values obtained experimentally are somewhat smaller than those 
obtained by calculation, where all of the oxygen is assumed to 
combine with hydrogen, forming water. 






























SUMMAKY OF EESULTS. 


29 


S. W. Parr® proposes a method for the determination of available 
hydrogen in coal by the use of curves which show the relation of 
available hydrogen to volatile carbon and total carbon. These 
curves are platted from the data of ultimate analyses, fixed points 
being established, and from available hydrogen values which were 
calculated by converting all of the oxygen to water. The sum of 
available hydrogen, volatile carbon, and sulphur is taken as com¬ 
bustible volatile and the difference between this and the total volatile 
as inert volatile. Many of the values thus deduced for the inert 
volatile matter are higher than those obtained in the present investi¬ 
gation by experimental measurement for the reason that in obtaining 
theni the presence of CO 2 and CO in the volatile products was not 
considered; but the experimental results of the present investigation 
uphold the contention of Parr and others that considerable propor¬ 
tions of inert noncombustible materials are contained in the volatile 
products of coal and that this factor varies with the type of coal. 

TESTS OF COAL IN PLATINUM RETORT. 

TOTAL GAS AT VARIOUS TEMPERATURES. 

In order to compare different coals in the amount and composition 
of their total gaseous products at medium and high temperatures, 
a series of tests was run in the platinum retort on 10 grams of 
coal, placed in the furnace at certain fixed temperatures and heated 
until gas practically ceased to be evolved. These tests were run in 
an atmosphere of nitrogen; the CO 2 and CO found are therefore 
products of destructive distillation, not of combustion. The gas 
analyses as given have been calculated to a nitrogen and oxygen free 
basis, it being assumed that any oxygen present is due to air admitted 
accidentally during the mixing and transferring of the gas sample. 
The volumes given under ^‘gas yieldhave also been corrected for 
air in a few instances where oxygen was shown by the analysis. No 
determinations of tar and water were made in these tests. Analyses 
of the different coals are found on page 25. 

Table 8.— Total gas yield and composition at different temperatures b 
[From 10 grams air-dried coal.] 


Coal No. 1 (Zeigler, III.). 


Temperature of furnace.° C.. 

500. 

600. 

700. 

800. 

900. 

1,000. 

1,100. 

Highest temperature reached in coal.° C.. 

390 

480 

585 

685 

811 

920 

1,026 

Gas at 25“ C.cubic centimeters.. 

197 

535 

980 

1,550 

2,335 

2,700 

3,120 

Con^osition of gas: 

23.8 

7.6 

6.4 

3.9 

2.5 

2.7 

1.8 

lUuminants. 

6.5 

5.0 

4.1 

3.3 

3.2 

3.7 

4.0 

CO. 

16.5 

16.1 

21.1 

16.9 

15.2 

15.1 

16.1 

CH^, CjHe, etc. 

49.5 

55.0 

41.5 

34.4 

27.8 

23.1 

19.4 

H . 

3.7 

16.3 

26.9 

41.5 

51.3 

65.4 

58.7 

Value of n In CnHsn+a. 

1.42 

1.29 

1.21 

1.16 

1.22 

1.18 

1.23 


a Jour. Am. Chem. Soc., vol. 29, 1907, p. 585; Bull. Illinois State Geol. Survey, No. 3,1906. 
t> Data given are averages of results of individual tests to be found elsewhere In this paper. 






















30 


THE VOLATILE MATTER OF COAL. 


Table 8. —Total gas yield and composition at different temperatures —Continued. 


Coal No. 3 (Connellsville, Pa.). 


Temperature of furnace.® C.. 

500. 

600. 

700. 

800. 

900. 

1,000. 

1,100. 

Highest temperature reached in coal.° C.. 

390 

474 

589 

705 

812 

922 

1,010 

Gas at 25° C.cubic centimeters.. 

Composition of gas: 

161 

718 

1,220 

1,723 

2,080 

2,900 

3,530 

15.9 

4.2 

3.2 

2.0 

1.1 

1.2 

1.0 

Illuminants. 

9.1 

7.1 

4.3 

4.5 

4.8 

4.6 

5.2 

CO. 

7.8 

6.0 

6.3 

7.2 

7.4 

6.4 

7.3 

CHi, CjHfi, etc. 

63.3 

64.4 

55.8 

47.0 

33.2 

29.0 

26.3 

H. 

3.9 

18.3 

30.4 

39.3 

53.5 

58.8 

60.2 

Value of n in CnH 2 n +2 . 

1.69 

1.37 

1.27 

1.21 

1.22 

1.11 

1.15 



Coal No. 16 (Poca¬ 
hontas). 

Coal No. 11 (Dietz, 
Wyo.). 

Temperature of furnace.° C.. 

500. 

700. 

1,000. 

500. 

700. 

1,000. 

Highest temperature reached in coal.° C.. 


615 

920 


600 

920 

Gas at 25° C.cubic centimeters.. 

238 

1,185 

3,230 

517 

1,300 

3,650 

Composition of gas: 







CO 2 . 

5.5 

1.4 

.4 

54.3 

21.7 

10.4 

Illuminants. 

5.2 

3.5 

3.7 

3.7 

3.5 

4.5 

CO. 

3.5 

5.1 

4.6 

19.6 

21.5 

22.3 

cm, CjHe, etc. 

70.6 

55.2 

26.8 

18.9 

29.4 

16.3 

H. 

15.2 

34.8 

64.5 

3.5 

23.9 

46.5 

Value of n in CnH 2 n +2 . 

1.46 

1.19 

1.13 

1.55 

1.19 

1.25 


Table 9. — Yield of different gaseous products at 500°, 700°, and 1,000° C . 


[Cubic centimeters from 10 grams of coal.) 


Temperature of fur¬ 
nace .° C . 

1 500. 

700. 

1,000. 

No. of coal. 

16. 

3- 

1. 

11. 

16. 

3. 

1. 

11. 

16. 

3. 

1. 

11. 

Total gas. 

238 

161 

197 

517 

1,185 

1,220 

980 

1,300 

3,230 

2,900 

2,700 

3,650 

CO 2 . 

13 

26 

47 

281 

17 

39 

63 

282 

13 

35 

73 

380 

Illuminants. 

12 

15 

13 

19 

42 

52 

40 

46 

120 

133 

100 

164 

CO. 

8 

13 

33 

101 

60 

77 

207 

280 

149 

186 

408 

814 

CH^, C 2 H 6 , etc. 

168 

102 

97 

98 

654 

681 

407 

382 

866 

841 

624 

595 

H. 

37 

5 

7 

18 

412 

371 

263 

310 

2,082 

1,705 

1,495 

1,697 

Value of n in CnH 2 n+ 2 . 

1.46 

1.69 

1.42 

1.55 

1.19 

1.27 

1.21 

1.19 

1.13 

1.11 

1.18 

1.25 


The coals used in the tests above reported were selected as being 
representative of more or less well defined types and localities. 

No. 1 is from the Zeigler mine, in the so-called No. 7 seam of 
Illinois. It is representative of the noncoking Interior Province 
coals, among which it ranks high in heating value and steaming 
qualities. It has high volatile matter and gives trouble by the 
formation of mine gas. 

No. 3 is the well-known coking coal of Connellsville, Pa., of higher 
heating value and slightly lower volatile matter than No. 1. It is 
fairly representative of the high-grade steaming and coking coals of 
the Pittsburgh district. This type is commonly burned with large 
smoke production in boiler plants. 





































































TOO 800 9o 5 1000 500 600 700 800 900 1000 500 600 700 ^ 800 900 iOOO 

TEMPERATURE Of FURNACE. DEGREES CENTIGRADE 

Figure 3.—Total quantities of different gases from 10 grams of air-dried coal at different temperatures. 


SUMMARY OF RESULTS 


31 






















































































































































































































































































































































32 


THE VOLATILE MATTEK OF COAL. 


No. 16 is the well-known Pocahontas coal, representative of the 
high-grade, low-volatile, ^‘smokeless’^ coals of the lower West Vir¬ 
ginia region. This type has the highest heating value of American 
bituminous coals, has excellent coking properties, and, though low 
in volatile matter, gives a large quantity of ^Hhin^’ gas on destructive 
distillation. 

No. 11 is the subbituminous, low-grade coal of the Sheridan district, 
Wyoming, commonly known as black lignite.It is of low heating 
value, high oxygen content, and no coking properties; contains 20 



Figuee 4.—Smoky constituents of early volatile matter; 10 grams of air-dried coal heated ten minutes. 


to 24 per cent of moisture and 30 per cent of volatile matter and 
crumbles badly on exposure to the weather. It is commonly burned 
with very low efficiency in boiler plants. 

Table 9 and figure 3 show the absolute quantities (cubic centime¬ 
ters per 10 grams of coal) of the different gaseous constituents pro¬ 
duced at the several temperatures. The great amount of CO 2 and 
CO produced by the Wyoming and Illinois coals as compared to the 
yield of the eastern coals is very noticeable. The eastern coals, on 
the other hand, produce considerably greater amounts of hydrocar- 



































































































































SUMMARY OF RESULTS. 


33 


bons and hydrogen even at the low and medium temperatures. 
Hydrogen is given off more abundantly by the Pocahontas coal than 
by the others, at both low and high temperatures. As shown by the 
value of n in the saturated hydrocarbons CnH 2 n+ 2 ; the proportion of 
higher members of this hydrocarbon series is greater at low temper¬ 
atures than at high, and greater in the Connellsville type than in the 
others. In some tests less than 
half of these hydrocarbons is 
methane, the remainder being 
ethane and higher homologues. 


UJ 600 

iL 


t 


VOLATILE MATTER DURING EARLY 

PERIOD OF HEATING AT VARI¬ 
OUS TEMPERATURES. 

The character of the volatile 
matter produced during the 
early stages of heating has more 
direct bearing on economy in the 
utilization of fuel, on smoke pro¬ 
duction, and on the efficiency of 
furnaces than that of the vola¬ 
tile matter produced at later 
stages in the heating. It seems 
probable that in the first prod¬ 
ucts driven off is involved the 
chief difficulty in obtaining com¬ 
plete combustion. Accordingly, 
a series of experiments was un¬ 
dertaken to show comparatively 
the amount and character of the 
volatile products which differ¬ 
ent coals evolve during the first 
brief period of heating at vari¬ 
ous temperatures. In one series 
of experiments the period of 
heating was fixed by the time 
element alone, ten minutes be¬ 
ing adopted as the period best 
suited to the amount of coal and method of heating. In another 
series the rise of temperature in the interior of the coal itself was 
allowed to fix the period, the heating being stopped as soon as the 
inside temperature reached a point 200° below that of the furnace. 
By the latter method the period is, at the different temperatures, 


500 



a 


900 


TEMPERATURE OF FURNACE. DEGREES CENTIGRADE 
Figure 5.—Oxides of carbon in early volatile matter; 
10 grams of air-dried coal heated ten minutes. 







































































34 


THE VOLATILE MATTER OF COAL. 



TEMPERATURE OF FURNACE. DEGREES CENTIGRADE 

Figure 6.—Combustible gases and tar in early volatile matter; 10 grams of air-dried coal heated ten 

minutes. 




























































































































































































SUMMARY OF RESULTS. 


35 


more nearly in uniform relation to the total time of evolution of vola¬ 
tile matter. 

The coals used for the determination of total gas yield were used 
also in these experiments; and for the second series two others were 
added, No. 10, a high-volatile West Virginia gas coal, and No. 18, a 
high-volatile ^ dong flame bituminous coal from Diamondville, Wyo. 
The latter does not coke but is valued locally as a high-grade steam- 

































































































































































J 


















c 

)y 



















S 







































/ 



















/ 




















r 









( 




















/ 



















/ 




















t 



















J 




















f 



















/ 



















/ 




















/ 



















\ 
















w 

tv 


















—< 

r' 





























) 

} 



















/ 







































/ 




















/ 



















I 




















/ 

















h 


i 

















t- 


1 















u 

DT 



1 




















t 









































500 600 700 800 900 

TEMPERATURE OF FURNACE, DEGREES CENTIGRADE 


Figure 7.—Inert or noncombustible constituents (including moisture) of early volatile matter; 
10 grams of air-dried coal heated ten minutes. 

ing coal and is particularly well adapted to reverberatory furnaces 
in smelters, as it gives a long, hot flame. Determinations were made 
also of tar and water in this early volatile matter. 

TABULATED RESULTS, EARLY VOLATILE MATTER. 

The results, as compiled from the detailed data given later in the 
paper, are stated in Tables 10 to 13. The relation of the composi¬ 
tion and volume of the volatile matter to the temperature in the two 
series of experiments is shown graphically in flgures 4 to 9. 

































































36 


THE VOLATILE MATTER OF COAL. 



TEMPERATURE OF FURNACE. DEGREES CENTIGRADE 

Figure 8.—Smoky constituents of early volatile matter; 10 grams of air-dried coal heated to definite 

temperature. 


































































































































































COMBUSTIBLE GAS, CUBIC CENTIMETERS 


SUMMARY OF RESULTS 


37 




TEMPERATURE OF FURNACE. DEGREES CENTIGRADE 
Figure 9.—Combustible gases and tar in early volatile matter; 10 grams of 
air-dried coal heated to definite temperature. 





























































































































































Table 10. — Volatile matter in ten minutes^ heating of 10 grams of air-dried coal. 


38 


THE VOLATILE MATTER OF COAL. 


S 

bi) 

Ol 

N 


O 

5?; 

"cS 

o 

o 


o 

o 


O 

o 


<D 

O 

C3 

a 

u 

a 


Ui 

D 

C3 

<P 

04 

B 

H 


<N Tt< 


0 

00 

rH 

Tf4 cc »-< CO 05 

<N iC t>^ 10 05 

•s 

<N 

CO 


3 

Ph 

Fs 

> 

• 

0 

0 

00 

0 ic 
00 . . t- 
coco T}4 CO 

rH 

rH 

t>. 10 0 CD CO 

.CO 

rH CD 00 05 . 

Tf CO rH 






CO 05 05 

00 05 CD CO 0 

03 


CO . . <N 

.rt< 

• 

lO rH Ol 00 

CD CD 00 10 . 

C 

a 

0 

0 

0 

0 

rH 

bC (N rH 

CO 




. 


rH C5 0 

ICOC^ 1>.CDM 

0 


^ . . 05 

• • • • • 

5^; 

*3 

0 

0 

600. 

r}4 rH 

i>»o 1>-C^. 

rH rH 



IC • * 00 



CO 

CO 


Q 




w 

bH 


<» o ^ 
OXJ ^ 


04 


o 

o 


T3 

<D 

o 

C3 

(D 

b-t 

b4 

D 

c3 

t-i 

OI 

P4 

B 

0) 


w 

0) 

X3 


a 

<v 

o 

o 

D 

o 


CO 

cO 

b6 




CO 

.w 

a 

cO 

fl 


o 

•M 

C3 

to 

w 

c« 

o 


O S 

io.t; 

S'osooW 

Whi^oo 


+ 

a 


a 

O 

a 

• fM 

fl 

o 

03 

a 

*3 

> 


900 . 

9.1 

14.4 

2,240 

t-. CO CD rH CO 05 

.0 

CO CO 0 00 . 

rH CO ^ rH 

800 . 

0 b- »D <N 

00 . .ID 

CD 05 CO 

rH r. 
rH 

CO rH 0 CO CO 00 

t- . 

rH CO CO rH 

0 

0 

tD (N CD 0 

■f . • 

ID 00 CO CD 
rH 

ID ^ ID CO 

.(N 

05 CO CD CD . 

rH ^ rH 

0 

0 CO 

Tt- . . 

CD (N rH 
rH 

CD 0 00 <M ID 

.ID 

05 00 00 0 CO . 

rH ^ iD rH 

CD 



0 

• » 

ID • • 0 

Tf » 05 

CO • 

1 1 

9 

0 D 5 rr 0 • 
c 4 06 06 

ID rH <N 

ID 

1 • 

1 1 

1 f 

1 1 

• 

1 

• 

1 

• 

1 



♦<» 

03 

♦fH 

fi 


O 

Iz; 

O 


CO 

cO 

•M 

a 

o 

8 

p-i 

CO 

rH 

6 

;z; 

*3 

o 


o 

o 


03 

c 

b^ 

D 


03 

u 

O 

• 4 ^ 

C3 

Ut 

03 

P- 

s 

03 


900 . 

9.9 

24.3 

2,447 

CO h- 0 CO t- 

rH 05 05 . 

rH DJ rH CO rH 


• CO 0 

lDO5C0CDtrC^ 


• . . 00 

. Di 

• 

• 00 00 

rH CO 05 C<1 . 

0 

• rH •' 

rH CO rH 

0 

• rH 


00 

1 

1 

1 

1 



0 0 rH 0 

05 0 CO 


00 .c^ 

. (N 

• 

ID 00 00 0 

0 rH CD . 

0 

rH •s 

CO <N tH rH 

0 

rH 


• rj4 0 CO 

00 00 t >-0 


* *05 

.rf 

• 

• Di rH Di 

DJ CO rH rH • 

0 

• Dl 

CD rH rH 

CD 

• 

1 

t 

1 



• 0 ID 00 

ID ID CD 0 C<l 


• . t>- 

.CD 

• 

• (N 

rH ID DJ 

0 

• rH 

00 rH rH 

ID 

1 

1 

t 

• 



900. 

• t>- br t>* 

• , . CO 

• CD CO 

• <N 

• 

• 

• 

1 

00 CO 05 CD 

. 0 

rH CO ID . 

CO ID rH 


• t^rH 0 

Tj4 05 T}4 ID 00 <N 


• . . 05 

.CO 

• 

• CD 01 ID 

rH CO ID 0 00 . 

0 


'rJ4 T-l 

0 



00 

1 

1 

1 

9 



05 tr ID 

05 ID 05 CO 


05 . . 

.(N 

• 

ID Tt4 rH CD 

rH CO rH 00 . 

0 


CD <N rH 

0 







I 0 M CO 

!>• rH CO rH 00 00 


• . . 0 

.Tf 

• 

• rH rH 

0 05 CO (N . 

0 

« 

rH rH CD rH 

CD 

9 

1 

1 

4 



• CO 00 

* 4444 $ 

444444 

• 

• 0 

4 4 4 4 4 4 

0 

t 

444444 

8 

1 

1 

1 

1 

4 

4 4 4 4 4 4 

444444 

444444 

444444 

444444 


^■S 


. CO 

. . * b^ 

o 03 O ® 
073^ 

brf 

03 
P 4 

a 

03 
O 

C3 

«#«4 

D 

03 


CO 

o 

0 


03 

C3 

c3 

03 

Sm 

03 

b^ 

P 

>4^ 

C3 

bM 

03 

P 4 


03 

CO 
03 

.a 

b£ Ui 

2 cS 

WEh 


b£ 

O 


a 

c3 

a 


o 

03 

•s 


^ o :o 

is's :g •" 

oo5o„_ „ 

03 o 03 

^OO > 


04 

+ 

a 

04 


a 


a 

»F^ 

a 

IM 

o 


Computed to nitrogen and oxygen free basis. 

















































































































Table 11. —Quantities of different gases from ten minutes' heating of 10 grams of air-dried coal. 

[Cubic centimeters.] 


SUMMARY OF 


RESULTS. 


39 



•IT 

00 »-C o CO 
tH r-l 00 CO Cl 

C0<N cl »-4 . 


• 

60 

105 

22 

296 

157 

1.23 

• 

o 



o 

• 

CO 

CO o o 

40 kO 00 1-t Tj< 


16. 

CO CO o ^ 

tH Ol CO *-H 05 

TT 1-H . 


• 

rH 

^ O 

00 CO I-H CO 

^ • 



^ »-H 40 00 CO IC 

CO CO 1-H 00 40 


• 


# 

o 



o 

CO 

• 

CO 

r#« Oi 00 40 

^ T-H CO ^ 

rH • 



OiOcO^Cd^ 


16. 

* 


o 

o 


0<N 

OtH . <0 

o 


t-»t>»OcCO 

^ tH 


CO 


CO 


O 

o 


i 

E 

a 


2 

3 

w 

c« 

u 

& 

a 

•o 

H 


c5 

O 


O 


B6 


* H 1_L 

005M 


•■1 

•f 

ca 

w 

a 

O 

.2 

a 

o 

o 

3 





• 

423 

514 

66 

472 

971 

1.17 

• 

• 

CO C<l OS 

00 2m 00 O 

CO COO . 


• 

CO 

10 40000 0 

40 40 1-H 00 I-H 

l-H 1-H t-- O • 

•.^H 

rH 


• 

CD 

o) 40c<i 1-H r>. 

1 -H t>. CO o 

rH OOC^ . 

rH 


9 

383 

415 

52 

349 

582 

1.22 





• 

CO 1-H b- t-. 00 

40 rH 40 CO CD rH 

Ol Tfi . 

1-H 


• 

CO 

cocoo40'^eo 
<N iH 00 Q CO 
rH O 40 . 

TH 


16. 

CDC^ ^ cO(N 

00 CO t-- CO 

CD • 

rH 


o 

o 


0 ^ 

C 

c3 


3 

•m 

o 

a> 

(-> 

3 

05 

Im 

K 

a 


05 

O 

O 


O 


CO 

ChH 

i“- 


ooSqW> 


C4 

+ 

d 

c* 

w 

d 

O 

.2 

3 

o 

o 

3 

*3 


s 













































































40 


THE VOLATILE MATTER OF COAL 


Table 12. —Early volatile 'products in second series of tests. 

[ 10 grams of air-dried coai heated to definite temperatures, 200 ® below that of furnace.] 



Coal No. 1. 

Coal No. 3. 

Coal No. 16. 

Temperature of furnace. ° C.. 

600. 

750. 

900. 

600. 

750. 

900. 

600. 

750. 

900. 

Time heated.minutes.. 

8.5 

6.3 

4.8 

7.7 

7.5 

6.3 

8.2 

7.3 

5.8 

Tar.per cent.. 


6.9 

7.1 


9.3 

12.0 


3.6 

6.9 

Water.. .do_ 


14.1 

15.2 


4.7 

4.7 


2.3 

2.7 

Gas at 25° C., cubic centi- 










meters. 

150 

664 

1,568 

89 

817 

1,775 

65 

653 

1,640 

Composition ofgas:® 










CO 2 . 

28.2 

9.5 

6.6 

15.8 

3.5 

2.6 

13.7 

2.5 

1.8 

Illuminants. 

7.1 

4.1 

3.7 

9.2 

6.9 

7.0 

8.6 

4.9 

4.5 

CO. 

16.5 

15.4 

15.9 

7.1 

5.5 

7.4 

6.2 

3.7 

4.6 

CH 4 , CjHs, etc. 

45.7 

48.4 

32.3 

60.8 

61.4 

43.5 

63.8 

61.5 

44.0 

H. 

2.5 

22.6 

41.5 

7.1 

22.7 

39.5 

7.7 

27.4 

45. 1 

Value of n in Cn H 2 n +2 . 

1.38 

1 . 21 

1.19 

1.53 

1. 27 

1.18 

1.60 

1.24 

1.15 


Coal No. 11. 


Temperature of furnace.® C.. 


600. 


Time heated.minutes. 

Tar.per cent. 

Water.do... 

Gas at 25° C., cubic centi¬ 
meters. 

Composition ofgas;o 


10.1 


407 


750. 


6.5 

3.8 

21.2 

1,056 


CO2. 

Illuminants. 

CO. 

CH 4 , C 2 H 6 , etc.... 

H. 

Value of n in CnH 2 n +2 


59.8 
3.7 
20.3 
14.7 
1.5 
1.52 


30.5 

3.1 

20.7 

24.4 

21.3 

1.25 


900. 


3.7 

3.3 

22.6 

2,015 


Coal No. 18. 


600. 


6.8 


217 


750. 


5.9 

11.6 

11.2 

934 


900. 


5.0 

10.8 

11.9 

1,925 


Coal No. 10. 


600. 


6.6 


136 


750. 


6.7 

11.6 

4.9 

985 


18.9 

2.5 

23.6 

17.6 
37.4 
1.29 


28.9 

9.3 
17.5 
40.0 

4.3 
1.34 


10.9 

8.3 

17.3 

44.9 
18.6 
1.29 


8.2 
8.6 
18.2 
32.1 
32.9 
1.26 


12.7 

9.7 

6.2 

61.6 

9.8 

1.66 


4.1 
8.0 
5.8 
57.0 
25.1 
1.26 


900. 


6.0 

12.1 

4.9 

1,983 

2.7 
8.2 
7.6 
40.5 
41.0 
1.19 


a Computed to oxygen and nitrogen free basis. 

Table 13. — Volumes of various gases produced in second series of tests. 


TEMPERATURE OF FURNACE, 600°; OF COAL, 400®. 


No. of coal. 

16. 

3. 

10 . 

1 . 

18. 

11 . 

Time heated.minutes.. 

8.2 

7.7 

6.6 

8.5 

6.8 

10.1 

CO 2 . 

9 

14 

17 

42 

63 

243 

CO. 

4 

6 

8 

25 

38 

83 

Illuminants. 

6 

8 

13 

11 

20 

15 

CH 4 , C 2 H 6 , etc. 

41 

54 

84 

68 

87 

60 

H. 

5 

7 

14 

4 

9 

6 

Value of n in CnH 2 n +2 . 

1.60 

1.53 

1.66 

1. 38 

1.34 

1. 52 


TEMPERATURE OF FURNACE, 750°; OF COAL, 550°. 


Time heated.minutes.. 

7.3 

7.5 

6.7 

6.3 

5.9 

6.5 

CO 2 . 

16 

29 

40 

63 

102 

321 

CO. 

24 

45 

57 

102 

161 

219 

Illuminants. 

32 

56 

79 

27 

78 

33 

CH 4 , CjHe, etc. 

402 

502 

562 

322 

419 

258 

H. 

179 

185 

247 

150 

174 

225 

Value of n in CnH 2 n +2 . 

1.24 

1.27 

1.26 

1.21 

1.29 

1.25 


TEMPERATURE OF FURNACE, 900°; OF COAL, 700°. 


Time heated.minutes.. 

5.8 

6.3 

6.0 

4.8 

5.0 

3.7 

CO3. 

29 

46 

54 

103 

158 

381 

CO. 

75 

131 

150 

249 

350 

476 

Illuminants. 

74 

125 

163 

59 

166 

50 

CH4, C3Ht, etc. 

722 

772 

803 

506 

618 

355 

H. 

740 

701 

813 

651 

6.33 

763 

Value of n in CnH 2 n +2 . 

1.15 

1.18 

1.19 

1.19 

1.26 

1.29 






















































































































SUMMARY OF RESULTS. 


41 


CONCLUSIONS FROM RESULTS ON EARLY VOLATILE MATTER. 

The tabulated and platted data given above lead to several general 
conclusions. 

The early volatile products from the Illinois and Wyoming coals 
contain large proportions of inert constituents and of carbon monox¬ 
ide. At the lower temperatures also they contain more combustible 
gases than those from the eastern coals. Smoky constituents (shown 
in figs. 4 and 8) are greatest from the Connellsville coal and the West 
Virginia and Wyoming gas coals. Higher hydrocarbons, such as 
ethane, are produced in greatest abundance from the eastern coals; 
the quantity produced rises to a maximum at about 800°, then rap¬ 
idly falls on account of decomposition by heat. At furnace tempera¬ 
tures of 500° and 600° these higher hydrocarbons constitute about 
50 per cent of the total methane hydrocarbons. 

On the other hand, when the heating is continued only to a certain 
temperature in the coal, as in the second series of tests above (Tables 
12 and 13), the quantities of higher hydrocarbons increase continu¬ 
ously as a higher furnace temperature is used, for the time of heating 
grows less. 

Coals of the low-volatile bituminous type, represented by Poca¬ 
hontas coal, produce hydrogen abundantly on heating and also large 
amounts of methane hydrocarbons. 

It is indicated that smokeless combustion is more difiicult with 
coals of the Connellsville and the West Virginia “gas^’ types than 
with the southern Illinois and the Wyoming subbituminous types. 
On the other hand, certain western coals like that of Diamondville, 
Wyo., produce a rich smoky volatile matter at moderate tempera¬ 
tures in larger quantities than the eastern smoky coals. Coals of this 
Diamondville type, of which there are representatives in several 
different localities in the West, show every indication of being valu¬ 
able for the manufacture of illuminating gas and by-products. 

It is evident that the geologically older Appalachian coals, as com¬ 
pared to the younger western coals, contain a larger amount of 
bitumen or substances which readily liberate methane and ethane 
hydrocarbons and hydrogen. The western coals, on the other hand, 
in inverse ratio to their geologic age, produce larger amounts of CO^, 
CO, and water. The readiness with which CO 2 is liberated in large 
amounts even at the lower temperatures (300° to 500°) indicates the 
presence of compounds having the direct carbon-oxygen linking, such 
as the complex alcohols, aldehydes, or acids. 

VOLATILE MATTER AT ORDINARY TEMPERATURES AND AT 106° C. 

In connection with experiments on losses during storage of coal, 
the writers have noted the accumulation, in sealed bottles containing 
coal, of considerable amounts of methane and, in some cases, also, 


42 


THE VOLATILE MATTER OF COAL. 


of small amounts of CO 2 . Parr and Wheeler® have previously noted 
this accumulation of combustible gas from Illinois coals in sealed bot¬ 
tles, but did not collect or analyze the gas. The present writers hope 
to publish in another bulletin the results of a series of experiments 
on the storage of coal, in which will be embodied a large amount of 
data on the accumulation of gas. 

These experiments have shown also a remarkably rapid and long- 
continued absorption of oxygen by coal in storage, with some varia¬ 
tion among coals in respect to the amount and rapidity of the absorp¬ 
tion. R. T. Chamberlin in his “Notes on explosive mine gases and 
dusts,previously cited, demonstrates the continuous formation 
and accumulation of methane from coal in mines, and the rapid 
absorption by coal dust of oxygen from the air without forming COj. 

A series of experiments on the direct weighing of the products 
driven off in drying powdered coal for two hours at 105° C. showed 
slight losses of CO 2 (0.1 to 0.4 per cent) with coals from southern 
Illinois and the Sheridan field, Wyoming, but only traces of hydro¬ 
carbons. 

TEMPERATURE IN THE “OFFICIAL” VOLATILE-MATTER 
DETERMINATION. 

One gram of powdered coal was heated for seven minutes in the 
usual manner prescribed for the “official volatile-matter determina¬ 
tion, except that a hole was made in the crucible cover and a ther¬ 
mocouple inserted just under the surface of the coal. With coal No. 1 
(Illinois) the maximum temperature (830° C.) was reached in three 
minutes; with coal No. 3 (Connellsville) the maximum (838° C.) was 
reached in three minutes and a half. 

CALCULATION OF THE HEAT VALUE OF COAL FROM ITS ULTIMATE 

ANALYSIS. 

The experimental results given in the preceding pages show con¬ 
clusively that in the process of breaking down under the influence 
of heat the coal substance gives up its oxygen partly in the form of 
carbon-oxygen compounds and partly as the hydrogen-oxygen com¬ 
pound water. Some recent work by Vignon in Europe supports this 
conclusion.® The figures demonstrating this point are given again 
below in more compact form. 

a Bull. 17, Univ. Illinois Eng. Exper. Sta., 1907, p. 33. 
b Bull. U. S. Geol. Survey No. 383,1909. 
c Vignon, L., Bull. Soc. chlm., 4th ser., vol. 3, p. 109. 



SUMMARY OF RESULTS. 


43 


Table 14. — Oxygen relations in volatile matter. 


[Values are percentages of air-dried coal.] 


Coal. 

Per cent of oxygen com¬ 
pounds in volatile matter. 

Oxygen 
in CO 
and CO 2 . 

Oxygen 
in water. 

Total 
oxygen 
in dry 
coal. 

CO 2.0 

CO. 

Water of 
constitu¬ 
tion. 

No. 16 (Pocahontas): 

400-gram tests. 

10-gram tests. 

No. 3 (Connellsville): 

400-gram tests. 

0.44 

.90 

.72 

1.04 

1.66 

8.60 

8.80 

1.21 

1.74 

0.1 

1.5 

3.7 

3.5 

6.7 

7.5 

1.01 

1.65 

0.09 

1.33 

3.29 
3.10 

5.95 

6.67 

3.18 
3.18 

5.23 

5.23 

9.12 

16.63 

16.63 

10-gram tests. 

No. 1 (Zeigler, Ill.): 

10-gram tests. 

No. 11 (Sheridan, Wyo.; air dried): 

400-gram tests. 

10 gram tests. 

2.33 

4.90 

6.90 
8.10 

2.08 

4.01 

10.19 
11.03 





a There is a possibility of the formation of CO 2 in slight amount from the oxygen of air in contact with 
the coal at the beginning of a test. On the assumption that 500 cubic centimeters cf air is in contact with 
the coal, there could be formed, if all its oxygen entered into CO 2 , only 0.28 gram of CO 2 , or 0.07 per cent, 
on 400 grams of coal. 

Dulong's calculation of heat value from the ultimate analysis 
assumes that all of the oxygen of the coal combines with hydrogen of 
the coal during combustion, thereby neutralizing, so to speak, the 
calorific value of an amount of hydrogen equal to O-i-8. Dulong's 
calculation, as is well known, gives for many coals less calories than 
are shown by experimental determination. The coals exhibiting 
these discrepancies are usually medium and low grade coals, high in 
oxygen, which, as has been shown above, give up their oxygen in 
large part combined with carbon instead of with hydrogen. 

By combining with carbon instead of with hydrogen in the coal the 
oxygen exercises less anticalorific influence on the efficiency of the 
coal, as 1 gram of oxygen in combining with carbon to COj neutralizes 
three-eighths of a gram of carbon, or 3,030 calories; in combining with 
carbon to CO it partly neutralizes three-fourths of a gram of carbon, 
thus neutralizing f X 2,417 = 1,813 calories; whereas 1 gram of 
oxygen in combining' with hydrogen to H 2 O neutralizes one-eighth 
gram of hydrogen, or J X 34,460 = 4,308 calories. The anticalorific 
influence of a unit of oxygen in forming CO 2 or CO is therefore approx¬ 
imately 70 per cent or 42 per cent, respectively, of its influence when 
forming water. 

Before the Geological Society of Washington® David White called 
attention to the uniform anticalorific influence which oxygen has in 
coal and based partly on this factor a scheme for the classification of 
coals. In a later publication^ he concludes from a study of analytical 
data (on air-dried coal) that oxygen and ash appear to have nearly 
the same anticalorific value in coal. If this conclusion is correct, and 


o Science, vol. 27,1908, p. 537. 

6 White, David, The effect of oxygen in coal: Bull. U. S. Geol. Survey No. 383, pp. 8-21 and 3&-37. 
























44 


THE VOLATILE MATTER OF COAL. 


oxygen, like ash, has merely a diluting effect, its possible neutralizing 
effect in reducing the availability of hydrogen and carbon is not to 
be considered. A conclusion, however, that is probably nearer the 
truth is that oxygen has in some degree a neutralizing effect on 
hydrogen and carbon, since it is undoubtedly in chemical Tinion with 
these elements in the coal and appears in combination with them in 
the volatile products. This conclusion is supported by analytical 
data on moisture-free coal. Oxygen has not, on the other hand, as 
great a neutralizing effect as is assigned to it by Dulong^s formula, 
since, as demonstrated in the present paper, a portion of the oxygen 
neutralizes carbon rather than hydrogen. 

If the heat values of an Illinois coal (No. 19) and of a Wyoming 
coal (No. 11) are calculated by Dulong’s formula and by formulas 
based on the distribution of oxygen between H 2 O, CO, and CO 2 accord¬ 
ing to the experimental results herein set forth, the following values 
are found: 


Composition and heat value of Illinois and Wyoming coals. 



Illinois 
(No. 19).o 

Wyoming 
(No. 11).6 

Composition (water free): 

Ash. 

6.16 

5.56 

Carbon. 

76.96 

68.90 

Hydrogen. 

4.49 

4.56 

Nitrogen... 

1.52 

1.51 

Sulphur. 

.52 

.51 

Oxygen. 

10.35 

18.96 

Calories: 

Dulong’s calculation. 

7,322 

7,453 

7,536 

6,333 

6,524 

6,582 

Modified calculation. 

Determined. 



a From Zeigler, Franklin County, Ill. 
b From Dietz, near Sheridan, Wyo. (subbltuminous). 


The formulas used for the modified calculation are the following: 
Illinois type: 

Calorificvalue = 8,080 (C — 0.120 X O) + 34,460(11 — 0.063 X O) + 2,250 S. 
Wyoming type: 

Calorific value = 8,080(0 — 0.182 x O) -f-34,460(11 —0.050 xO) -1-2,2508. 
















DETAILED DATA OF TESTS, 


45 


DETAILED DATA OF INDIVIDUAL TESTS. 


Full details of the results on which the conclusions presented 
this bulletin are based are given in the subjoined tables: 

Table 15 .—Results of hy-product tests of 400 grams of coal. 


Coal 

No. 

Test 

No. 

Coke(per 
cent). 

Tar (per 
cent). 

Water 

(per 

cent). 

Ammonia 
(pounds 
of sul¬ 
phate per 
ton). 

CO 2 (per 
cent). 

H 2 S (per 
cent). 

Gasat0°C. 

and 30 
Inches of 
mercury 
(cubic feet 
per ton). 

16 

33 

79.1 

7.2 

1.0 

13.2 

0.44 

0.08 

10,180 

16 

34 

79.1 

7.2 

1.5 

12.5 

.43 

.06 

9,210 

3 

39 

73.5 



25.0 

.71 

.28 

8,650 

3 

41 

70.8 

13.7 

2.4 

22.8 

.72 

.21 

8,670 

3 

42 

70.3 



22.0 



8,080 

3 

43 

70.8 

11.3 

5.1 

22.8 



7,840 

3 

47 

72.2 

10.5 

5.6 

25.5 



8,000 

3 

50 

70.5 

9.8 

6.4 

24.4 



7,800 

o3 

48 

67.1 

8.5 

14.1 

24.1 



6,960 

a3 

49 

66.0 

9.8 

12.5 

24.5 



6,325 

23 

31 

63.1 

12.3 

11.0 

26.4 

1.20 

.47 

8,400 

23 

32 

63.1 

11.5 

10.3 

24.1 

1.19 

.44 

8,400 

11 

22 

44.8 

6.9 


28.4 

8.10 

.08 

7,850 

11 

24 

44.4 

8.2 

26.5 

25.5 

8.22 

.07 

7,890 

11 

25 

44.9 

6.5 

27.0 

25.9 




11 

40 

45.0 

6.8 

29.0 

29.1 

8.03 

.10 

7,760 

b 11 

36 

52.9 

5.3 

19.0 

28.2 

8.62 

.12 

8,540 

bll 

37 

53.1 

5.6 

19.0 

25.1 

8.20 

,10 

7,790 

25 

51 

58.4 

12.1 

11.5 

25.8 

3.07 

.25 

7,640 

25 

53 

58.7 

12.4 

12.0 

26.7 

3.20 

.22 

7,600 

46 

54 

63.3 

9.9 

10.8 

25.5 

1.86 

.30 

7,950 

46 

57 

64.4 

10.6 

9.2 

27.1 

1.73 


7,930 


o Coal moistened to 9.6 per cent of moisture. 
b Air-dried coal, 11.5 per cent of moistura. 


in 

























46 


THE VOLATILE MATTER OF COAL, 


Table 16 .—Analyses of samples of gas obtained successively during by-product tests. 

{The analyses under each test are stated in order in which they were made. Unless otherwise specified 

COj was removed from gas during test.] 


Coal and test Nos. 

Composition of gas. 

Value of 
n In 

CnHjn4-1. 

CO 2 . 

Illuml- 

nants. 

0. 

0 

p 

CH 4 , 
CaHe, etc. 

H. 

N. 

Coal 16: 









Test 33. 

0 

3.5 

0.5 

2.8 

38.2 

42.7 

12.3 

(«) 


0 

1.6 

.4 

4.0 

31.0 

62.5 

.5 

(«) 


0 

.6 

.0 

.8 

5.8 

87.9 

5.0 

(«) 


0 

0 

.2 

.8 

3.1 

88.3 

7.6 

(“) 

Test 34. 

.2 

3.4 

,4 

0 

59.6 

31.7 

.7 

(«) 


0 

2.0 

.2 

4.4 

33.0 

57.5 

2.9 

(») 


0 

0 

.2 

1.0 

5.9 

87.7 

5.2 

(«) 


0 

0 

.3 

.9 

3.7 

89.1 

6.0 

(«) 

Coal 3: 









Test 39. 

0 

5.1 

.5 

6.1 

43.5 

37.6 

7.2 

1.25 


0 

2.4 

.3 

6.3 

19.3 

66.7 

5.0 

1.18 

Test 41. 

0 

5.7 

5.4 

4.1 






0 

4.7 

.5 

5.8 

43.4 

42.3 

2.3 

1.19 


0 

0 

0 

3.4 

6.8 

84.5 

5.3 



.4 

0 

.2 

3.2 

4.7 

85.4 

6.1 


Test 42. 

53.4 

6.2 

1.6 

5.2 

49.5 

22.0 

12.1 

1.34 


2.1 

3.8 

.5 

6.4 

39.0 

45.4 

2.8 

1.18 


.6 

.2 

.4 

3.6 

8.3 

83.3 

3.6 



0 

.4 

0 

2.4 

8.5 

84.3 

4.4 


Test 43. 

4.2 

5.5 

0 

5.3 

51.1 

25.8 

8.1 

1.31 


2.1 

4.2 

0 

6.3 

36.3 

47.5 

3.6 

1.22 


.4 

.2 

0 

5.8 

12.0 

79.3 

2.3 


Test 47. 

6 3.3 

5.0 

.3 

5.3 

55.4 

27.4 

3.4 

1. 26 

Test 48. 

3.7 

4.6 

.8 

5.4 

51.6 

29.9 

4.0 

1.28 


2.4 

3.0 

.1 

5.4 

35.7 

51.7 

1.7 

1.14 


.5 

.5 

0 

2.8 

9.5 

83.5 

3.2 


Test 49. 

6 4.2 

5.4 

.7 

5.1 






2.9 

3.5 

.4 

6.5 

46.4 

38.4 

1.9 

1.21 


1.4 

.7 

0 

4.6 

17.0 

73.7 

2.6 


Coal 23: 









Test SI. 

0 

5.1 

.8 

7.1 

34.5 

35.5 

17.0 

(«) 


0 

4.5 

0 

9.4 

32.4 

50.9 

2.8 

(«) 


0 

0 

.1 

5.7 

7.3 

80.4 

6.5 

(«) 


0 

0 

0 

3.2 

3.0 

81.9 

11.9 

(“) 

Test 32. 

0 

4.4 

.5 

6.8 

57.7 

27.1 

3.5 

(«) 


0 

4.2 

.6 

9.2 




(o) 


0 

.1 

0 

7.3 

13.8 

76.4 

2.4 

(<*) 


0 

0 

0 

4.3 

6.2 

80.7 

9.0 

(“) 

Coal 11: 









Test 22. 

.9 

3.5 

.2 

12.3 

20.4 

50.0 

12.9 

(“) 


5.8 

1.6 

.3 

24.2 

9.3 

49.5 

9.3 

(a) 


2.6 

0 

.4 

22.9 

6.5 

57.4 

10.2 

(®) 

Test 24. 

4.0 

3.4 

.2 

12.1 

22.1 

51.7 

6.5 

(«) 


5.4 

1.8 

.2 

21.9 

18.4 

49.9 

2.4 

(®) 


.3 

.1 

.2 

27.5 

7.1 

55.6 

9.2 

(«) 

Test 25. 

7.4 

2.6 

.3 

10.3 

20.2 

52.5 

6.7 

(«) 


10.0 

2.2 

.4 

17.9 

19.0 

47.3 

3.2 

(“) 


5.6 

.2 

.2 

27.6 

5.9 

50.9 

9.6 

(«) 

Test 40. 

1.4 

4.8 

2.2 

19.2 


29.8 




5.2 

1.6 

.3 

22.4 

12.4 

50.3 

7.8 


Coal 11 (air dried): 









Test 36. 

11.7 

3.5 

.5 

17.7 

37.2 

23.4 

6.0 

(«) 


12.2 

2.6 

0 

19.5 

22.4 

40.8 

2.5 

(«) 


2.4 

1.0 

.4 

18.4 

14.2 

57.1 

6.5 

(a) 


.1 

0 

.3 

10.2 

9.5 

68.0 

11.9 

(«) 

Test 37. 

14.0 

3.7 

.2 

16.2 

33.5 

25.7 

6.7 

(a) 


11.4 

2.9 

.3 

19.9 

23.9 

38.3 

3.3 

(®) 


0 

0 

0 

22.2 

12.3 

58.0 

7.8 

(«) 

Coal 25: 









Test 51. 

.4 

7.8 

0 

12.6 

52.0 

21.3 

5.9 

1.33 


.8 

9.2 

0 

14.8 

35.2 

36.6 

3.4 

1. 33 


.5 

.9 

0 

13.9 

9.2 

68.8 

6.7 

1.34 


.5 

.6 

.3 

7.5 

5.7 

76.4 

9.0 

1.71 

Coal 46: 









Test 54. 

0 

9.1 

0 

13.4 

41.9 

30.3 

5.3 

1.40 


1.5 

9.5 

.2 

13.6 

25.7 

46.3 

3.2 

1.33 


0 

.4 

.2 

10.0 

5.3 

77.8 

6.3 

1.68 

Test 57. 

1.3 

7.2 

0 

13.3 

45.2 

32.2 

.8 

1.31 


0 

6.3 

.4 

12.9 

26.1 

51.4 

2.9 

1.25 

- 

.2 

.5 

.2 

8.2 

6.9 

78.2 

5.8 

1.48 


a Not determined, as H was not separately determined. 
COi not removed during test. 


















































DETAILED DATA OF TESTS 


47 


Table 17. —Analyses of total gas from by-product tests. 


Coal No. 

Test 

No. 

Composition of gas.o 

Value 
of n in 
CnH2ii+2. 

Illumi- 

nants. 

CO. 

CH4, 

CjHfi, 

etc. 

H. 

N. 

16 

33 

1.8 

3.1 

26.0 

69.0 

.1 

(") 

16 

34 

1.0 

3.3 

26.8 

66.5 

2.4 

(») 

3 

39 

3.5 

5.2 

26.4 

60.4 

4.5 

1.23 

3 

41 

3.9 

5.0 

21.4 

66.5 

3.3 

1.46 

3 

42 

3.3 

5.2 

29.3 

59.9 

2.3 

1.19 

3 

43 

3.3 

4.9 

30.1 

58.8 

2.9 

1.18 

3 

47 

2.7 

5.2 

•30.3 

58.1 

3.7 

1.26 

3 

50 

2.7 

5.2 

29.3 

61.0 

1.8 

1.29 

3 

48 

2.9 

5.0 

33.3 

58.3 

.5 

1.12 

3 

49 

2.7 

5.4 

34.7 

53.2 

4.0 

1.22 

23 

31 

3.0 

7.3 

29.7 

56.3 

3.7 

(«») 

23 

32 

2.9 

7.5 

22.8 

57.3 

9.5 

(&) 

11 

22 

2.0 

19.9 

19.0 

53.9 

5.2 

(*>) 

11 

24 

1.9 

20.0 

18.9 

53.7 

5.5 

(») 

11 

40 

2.6 

17.8 

18.1 

54.0 

7.5 

1.18 

. cll 

36 

2.5 

21.2 

21.4 

51.6 

3.3 

(*>) 

cll 

37 

2.6 

21.6 

23.7 

47.0 

5.1 

('>) 

25 

51 

5.8 

14.0 

27.4 

47.7 

5.1 

1.38 

25 

53 

5.6 

15.9 

27.0 

47.6 

3.9 

1.25 

46 

54 

6.3 

12.8 

24.7 

51.6 

4.6 

1.32 

46 

57 

4.6 

11.9 

25.8 

53.9 

3.8 

1.25 


a Reduced by calculation to CO 2 and air-free basis. 

Not determined, as H was not separately determined, 
c Air-dried coal. 


Table 18. — Total gas obtained from 10 grams of air-dried coal. 
COAL NO. 1 (ZEIGLER, ILL.). 


Temperature of furnace.°C.. 

500. 

600. 

700. 

Test No. 

60 

226 

71 

78 

68 

81 

Highest temperature in coal.°C.. 

390 


490 

470 

580 

575 

Time to reach highest temperature, 







minutes. 

20 


17 

20 

16 

18 

Gas at 25° C.cubic centimeters.. 

130 

264 

570 

500 

965 

990 

Composition of gas: 

As collected— 







CO 2 . 

7.5 

10.7 

4.8 

5.1 

4.2 

5.0 

Illuminants. 

2.0 

3.1 

3.0 

3.4 

2.5 

3.4 

0. 

1.8 

.5 

.5 

.3 

.7 

.4 

CO. 

4.8 

8.3 

10.7 

10.0 

17.7 

13.0 

CH 4 , C 2 H 6 , etc. 

11.3 

32.2 

37.3 

33.2 

33.9 

26.7 

H. 

.0 

4.4 

8.9 

12.0 

17.8 

21.1 

N. 

72.6 

40.8 

34.8 

36.0 

23.2 

30.4 

Computed to N and O free basis— 

CO 2 . 

29.3 

18.2 

7.4 

8.0 

5.5 

7.2 

Illuminants. 

7.8 

5.2 

4.6 

5.3 

3.3 

4.9 

CO. 

18.8 

14.2 

16.5 

15.7 

23.3 

18.8 

CH 4 , C 2 H 6 , etc. 

44.1 

54.9 

57.7 

52.2 

44.5 

38.6 

H..!.!. 

.0 

7.5 

13.8 

18.8 

23.4 

30.5 

Value of n in CnH 2 n +2 . 

1.48 

1.36 

1.21 

1.36 

1.18 

1.23 












































48 


THE VOLATILE MATTER OF COAL 


Table 18. —Total gas obtained from 10 grams of air-dried coal —Continued. 
COAL NO. 1 (ZEIGLER, ILL.)—Continued. 


Temperature of furnace.®C.. 

800. 

900. 

1,000. 

1,100. 

Test No. 

85 

93 

88 

97 

90 

99 

Highest temperature in coal.°C.. 

679 

691 

797 

a 832 

920 

1,026 

Time to reach highest temperature, 







minutes. 

12 

12 

10 

8 

7 

6 

Gas at 25® C.cubic centimeters.. 

1,500 

1,600 

2,290 

2,380 

2,700 

3,120 

Composition of gas: 







As collected— 







CO 2 . 

3.0 

3.4 

2.0 

2.4 

2.2 

1.6 

Illuminants. 

3.0 

2.4 

3.2 

2.4 

3.1 

3.6 

0. 

.4 

.2 

.3 

1.0 

1.5 

.3 

CO.. . 

14.0 

13.9 

13.6 

13.2 

12.5 

14.0 

CHi, C 2 H 6 , etc. 

25.0 

32.1 

24.0 

25.1 

19.2 

16.9 

H. 

35.4 

33.3 

45.0 

45.4 

46.0 

51.2 

N. 

Computed to N and 0 free basis— 

(5o2. 

19.2 

14.7 

11.9 

10.5 

15.5 

12.5 

3.7 

4.0 

2.3 

2.7 

2.7 

1.8 

Illuminants. 

3.7 

2.8 

3.7 

2.7 

3.7 

4.0 

CO. 

17.5 

16.3 

15.5 

14.9 

15.1 

16.1 

CHi, C 2 H 6 , etc. 

31.1 

37.8 

27.3 

28.4 

23.1 

19.4 

H. 

44.0 

39.1 

51.2 

51.3 

55.4 

58.7 

Value of n in CnH 2 n +2 . 

1.17 

1.15 

1.26 

1.18 

1.18 

1.23 


o Test run in air instead of in nitrogen. 


COAL NO. 3 (CONNELLSVILLE, PA.). 


Temperature of furnace.°C.. 

500. 

600. 

700. 

Test No. 

61 

227 

79 

84 

77 

82 

Highest temperature in coal.®C.. 

390 


487 

478 

577 

577 

Time to reacla highest temperature.minutes.. 

24 


14 

15 

13 

17 

Gas at 25° C_T.t.cubic centimeters.. 

150 

172 

730 

705 

1,280 

1,160 

Composition of gas: 







As collected— 







CO 2 . 

3.8 

4.8 

2.8 

2.6 

2.6 

1.8 

Illuminants. 

1.8 

3.7 

4.4 

4.6 

3.5 

3.0 

0. 

3.1 

.8 

.8 

.5 

.1 

.8 

CO. 

1.8 

2.4 

4.6 

3.1 

4.2 

4.8 

CH 4 , C 2 H 6 , etc. 

9.5 

34.0 

43.9 

38.8 

41.4 

42.4 

H. 

.0 

3.9 

13.2 

10.6 

23.5 

22.5 

N. 

80.0 

50.4 

30.3 

39.8 

24.7 

24.7 

Computed to N and 0 free basis— 







CO 2 . 

22.0 

9.9 

4.0 

4.4 

3.8 

2.5 

Illuminants. 

10.6 

7.6 

6.3 

7.8 

4.5 

4.1 

CO. 

10.6 

5.0 

6.6 

5.3 

5.6 

6.9 

CHi, C 2 H 6 , etc. 

56.8 

69.7 

64.0 

64.9 

55.1 

56.6 

H. 

0 

7.8 

19.1 

17.6 

31.0 

29.9 

Value of n in CnH 2 n +2 . 

1.87 

1.50 

1.39 

1.35 

1.31 

1.23 


Temperature of furnace.°C.. 

800. 

900. 

1,000. 

1,100. 

Test No. 

87 

94 

89 

92 

106 

Highest temperature in coal.°C.. 

689 


810 

9 

2,080 

922 

7 

2,900 

1,008 

5 

3,530 

Time to reacli highest temperature.minutes.. 

Gas at 25° C.cubic centimeters.. 

11 

1,685 

1,760 

Composition of gas: 

As collected— 



CO 2 . 

1.6 

2.0 

.8 

1.0 

1.0 

Illuminants. 

3.8 

3.6 

3.5 

4.0 

4.6 

0. 

.5 

.2 

3.7 

5.4 

.2 

.3 

CO. 

6.2 

6.4 

5.6 

6.6 

CH 4 , C 2 H 6 , etc. 

H. 

40.9 

34.2 

40.5 

33.9 

24.2 

39.0 

25.9 

52.9 

23.9 

54.8 

N. 

12.8 

13.4 

23.4 

10.4 

8.8 

Computed to N and 0 free basis— 

COi. 





1.7 

2.3 

1.1 

1.2 

1.0 

Illuminants. 

4.7 

4.2 

4.8 

4.6 

5.2 

CO. 

7.1 

7.4 

7.4 

6.4 

7.3 

CH 4 , C 2 H 6 , etc. 

47.1 

46.9 

33.2 

29.0 

26.3 

H. 

39.4 

39.2 

53.5 

58.8 

60.2 

Value of in CnH 2 n +2 . 

1.24 

1.18 

1.22 

1.11 

1.15 



























































































DETAILED DATA OF TESTS 


49 


Table 18. Total gas obtained from 10 grams of air-dried coal —Continued. 
COALS NO. 16 (POCAHONTAS, VA.) AND NO. 11 (DIETZ, WYO.). 



Coal No. 16. 

Coal No. 11. 

Temperature of furnace.°C 

500. 

700. 

1,000. 

500. 

700. 

1,000. 

Test No. 

229 

230 

96 

100 

107 

228 

101 

104 

Highest temperature in coal.°C. 



612 

617 

920 


600 

920 

Time to reach highest temperature, 





minutes. 



13 

14 

8 


in 

0 

Gas at 25® C.cubic centimeters.. 

240 

236 

1,190 

1,175 

3,230 

517 

1,300 

3,650 

Composition of gas: 









As collected— 









CO 2 . 

2.8 

3.0 

1.0 

1.2 

.4 

39.8 

17.9 

9.4 

lUuminants. 

2.8 

2.8 

2.8 

2.8 

3.4 

2.7 

2.9 

4.1 

0 . 

.8 

.7 

.4 

.4 

.4 

.2 

.3 

.5 

CO. 

2.3 

1.9 

4.2 

4.0 

4.2 

14.4 

17.7 

20.2 

CH4,C2H6,etc. 


38. 4 

45.0 

44.2 

24 5 

13 9 

24 2 

li 7 

H. 


8.3 

27. 5 

28.8 

59 0 

2 5 

19 6 

42 1 

N. 


44.9 

19.1 

18.6 

8.1 

26.5 

17.4 

9.0 

Computed to N and O free basis— 




CO 2 . 


5.5 

1.3 

1.5 

.4 

54 3 

21 7 

10 4 

lUuminants. 


5.2 

3.5 

3. 5 

3.7 

3 7 

3 5 

4 5 

CO. 


3.5 

5.2 

4.9 

4. 6 

19. 6 

21 5 

22 3 

CH4,C2H6, etc. 


70.6 

55.9 

6 

26.8 

18.9 

29. 4 

16 3 

H..:....:;.. 


15.2 

34.1 

3'5. 5 

64. 5 

3.5 

23. 9 

46 5 

V alue of n in CnH 2 n +2 . 


1.46 

1.17 

1.21 

1.13 

1.55 

1.19 

1.25 


Table 19. —Early volatile 'products from ten minutes^ heating of 10 grams of air-dried 

coal. 

COAL NO. 1 (ZEIGLER, ILL.). 


Temperature of furnace.®C.. 

500. 

600. 

700. 

^00. 

900. 

Test No. a . 

59 

69 

73 

62 

231 

76 

83 

132 

Highest temperature in coal.®C.. 

345 

445 

435 

550 

540 

670 

689 


Tar. i .per cent.. 


6.3 

7.1 

7.9 

8.5 

9.7 


9.1 

Water.. .do_ 


11.8 

12.7 

13.9 

13.3 

13.5 


14. 4 

Gas at 25° C.cubic centimeters.. 

90 

175 

171 

485 

800 

1,224 

1,280 

2,240 

Composition of gas: 









As collected— 









CO 2 . 

5.0 

7.8 

7.7 

6.4 

7.5 

3.2 

3.4 

3.3 

lUuminants. 

0 

3.4 

3.5 

3.9 

2.8 

3.2 

3.2 

2.9 

0. 

2.6 

.9 

.3 

.9 

.3 

.2 

.3 

.6 

CO. 

1.8 

6.3 

8.0 

10.4 

13.1 

14.6 

13.3 

13.0 


2.7 

22.6 

18.3 


36.9 


.29.5 

26.7 

H . 

0 

2.3 

.4 


19.6 


29.5 

42.9 

N . 

87.9 

56.7 

61.8 


19.8 


20.8 

10.6 

Computed to 0 and N free basis— 









CO 2 . 

52.7 

18.5 

20.3 


9.4 


4.3 

3.7 

Tlliiminants . 

0 

8.0 

9.2 


3.5 


4.1 

3.3 

CO . 

18.9 

14.9 

21.1 


16.4 


17.0 

14.6 

CTT,) C 2 Hg, etc . 

28.4 

53.3 

48.3 


46.2 


37.3 

30.1 

H . 

0 

5.3 

1.1 


24.5 


37.3 

48.3 

Value of n in C^H} ^ ?. 


1.48 

1,62 


1.23 


1.18 

1.09 

# 










a Number of test applies to test for gas only, 






































































































50 THE VOLATILE MATTER OF COAL. 


Table 19. —Early volatile products from ten minutes^ heating of 10 grams of air-dried 

coal —Continued. 


COAL NO. 3 (CONNELLSVILLE, PA.). 


Temperature of furnace. 

.°C.. 

500. 

600. 

700. 

Test No. 


66 

70 

72 

75 

64 

Highest temperature in coal.. 

.°C.. 

335 

455 

452 

415 

565 

Tar. 

.per cent.. 


5.1 

5.3 


12.6 

Water. 

.. .do_ 


3.1 

2.7 


3.2 

Gas at 25° C. 

. .cubic centimeters.. 

8 

162 

233 

176 

668 

Composition of gas; 







As collected— 







CO, __ 



3.2 

3.0 

3.2 

2.6 

Illuminants. 


4.2 

4.0 

4.3 

5.8 

0. 


.5 

.9 

.6 

.3 

CO. 


2.9 

2.9 

3.2 

3.7 



23.6 

39.1 

30.8 


H.J^.r..*'. 


2.6 

.3 

.0 


N. 


63.0 

49.8 

57.9 


Computed to 0 and N free basis— 






CO,_ 



8.8 

6.1 

7.7 


Illuminants. 


11.5 

8.1 

10.4 


CO. 


8.0 

5.9 

7.7 


CH^, C 2 H 6 , etc. 


64.6 

79.3 

74.2 


H. . 


7.1 

.6 

0.0 


Value of n in CnH 2 n +2 . 


1.65 

1.20 

1.40 









Temperature of furnace.°C.. 

700. 

800. 

900. 

Test No. 

65 

232 

80 

86 

133 

Highest temperature in coal.°C.. 

555 

565 

695 

679 


Tar.t.per cent.. 

10.6 


12.9 

13.5 

12.5 

Water.do_ 

2.7 


4.2 

3.8 

4.7 

Gas at 25° C.cubic centimeters.. 


990 

1,400 

1,350 

2,180 

Composition of gas: 




As collected— 






CO2. 

1.7 

2.3 

1.6 

1.0 

2.2 

Illuminants. 

4.7 

5.0 

5.3 

4.5 

4.8 

0. 

3.0 

.3 

.7 

.3 

.4 

CO. 

4.4 

4.7 

6.4 

5.9 

6.4 

CH4, C2H6, etc. 

35.4 

47.3 

36.0 

30.1 

31.9 

H. 

13.5 

22.8 

27.6 

31.7 

45.0 

N. 

37.3 

17.6 

22.4 

26.5 

9.3 

Computed to O and N free basis— 






CO2. 

2.8 

2.8 

2.1 

1.4 

2.4 

Illuminants. 

7.8 

6.1 

6.9 

6.1 

5.3 

CO. 

7.4 

5.7 

8.3 

8.1 

7.1 

CH4, C2H6, etc. 

59.2 

57.6 

46.8 

41.2 

35.3 

H. 

22.8 

27.8 

35.9 

43.2 

49.9 

Value of n in CnH 2 n +2 . 

1.50 

1.31 

1.25 

1.41 

1.19 


COAL NO. 16 (POCAHONTAS, VA.). 


Temperature of furnace.°C.. 

500. 

Test No. 

124 

0.3 

.8 

4 

Highest temperature In coal.°C.. 

Tar.per cent.. 

Water.do_ 

Gas at 25° C.cuDic centimeters.. 

Composition of gas: 

As collected— 

CO 2 . 

Illuminants. 


0. 


CO. 


CH4, CjHe, etc. 


H. 


N. 


Computed to 0 and N free basis— 

COs. 


Illuminants. 


CO. 


CH4, CsHb, etc. 


H. 


Value of n in CnHjn+j. 





600. 

700. 

800. 

900. 

119 

120 

122 

% 

103 

599 

115 

127 

131 

0.9 

1.0 


4.4 

6.7 

6.7 

6.7 

1.2 

1.3 


1.7 

2.1 

2.8 

2.7 

96 

40 

62 

675 

1,590 

2,325 

2,350 

3.6 

2.8 

3.0 

1.4 

1.1 

1.2 

1.6 

2.8 

1.6 

2.2 

3.2 

3.1 

3.2 

3.0 

.3 

1.6 

.5 

1.6 

.3 

.2 

.2 

2.2 

1.8 

1.9 

2.8 

4.3 

4.6 

4.4 

14.7 

11.1 

14.6 

44.1 

32.6 


32.3 

2.2 

0 

0 

20.3 

39.2 


49.4 

74.2 

81.1 

77.8 

26.6 

19.4 


9.1 

14.1 

16.2 

13.8 

1.9 

1.4 


1.8 

11.0 

9.2 

10.1 

4.5 

3.9 


3.3 

8.6 

10.4 

8.8 

3.9 

5.4 


4.9 

57.7 

64.2 

67.3 

61.4 

40.5 


35.6 

8.6 

0.0 

0.0 

28.3 

48.8 


54.4 

1.63 

1.48 

1.32 

1.27 

1.32 


1.07 
























































































































DETAILED DATA OF TESTS. 


51 


Table 19 .—Early volatile 'products from te'n minutes' heating of 10 grams of air-dried 

coal —Continued. 


COAL NO. 11 (DIETZ, WYO.). 


Temperature of furnace. °C 

d 

0 

600. 

Test No. 

121 

123 

116 

117 

118 

Highest temperature in coal."C.. 








2. 0 

3.0 

1 8 


Water. ^ . do . 


14.5 

22.0 

20.0 


Gas at 25° C.cubic centimeters.. 

94 

63 

350 

270 

260 

Composition of gas: 






As collected— 






CO2. 

29.4 

23.9 

34.0 

36.2 

36.5 

Illuminants. 

.4 

0 

2.2 

2.1 

2.2 

0 . 

.8 

.5 

.4 

.4 

.7 

CO. 

5.6 

4.6 

14.0 

11.6 

11.5 

CHi, C2H6, etc. 

.4 

1.1 

9.8 

5.6 

4.7 

H. 

0 

0 

0 

0 

0 

N.•. 

63.4 

69.9 

39.6 

44.1 

44.4 

Computed to O and N free basis— 






CO2. 

82.2 

80.7 

56.7 

65.2 

66.5 

Illuminants. 

1.1 

0 

3.7 

3.8 

4.0 

CO. 

15.6 

15.6 

23.3 

20.9 

20.9 

CH4, C2H6, etc. 

1.1 

3.7 

16.3 

10.1 

8.6 

H. 

0 

0 

0 

0 

0 

Value of n in CnH2n+j. 

1.25 

2.00 

1.22 

1.48 

1.62 


700. 

800. 

900. 

105 

114 

126 

128 

580 




8.6 

8.3 

9.8 

10.0 

18.1 

18.7 

24.8 

23.9 

1,020 

1,780 

2,400 

2,350 

24.8 

18.0 

14.4 

15.7 

3.2 

2.4 

2.4 

1.2 

.2 

.2 

.3 

.5 

17.2 

19.5 

20.7 

21.8 

22.0 

16.4 



13.1 

27.3 



19.5 

16.2 



30.9 

21.5 



4.0 

2.9 



21.4 

23.3 



27.4 

19.6 



16.3 

32.7 



1.27 

1.22 




Temperature of furnace."C. 


Test No. 

Highest temperature in coal.®C 

Tar.per cent 

Water.do.. 

Gas at 25°C.cubic centimeters 

Composition of gas: 

As collected— 

CO 2 . 

Illuminants. 

O. 

CO. 

CH 4 , C 2 H 6 , etc. 

H. 

N. 

Computed to O and N free basis— 

CO 2 .. 

Illuminants. 

CO. 

CH<, C 2 H 6 , etc. 

H. 

Value of n in CnH 2 n+i. 


130 


2,590 


15.4 

2.4 

.2 

18.7 
17.1 

35.3 
10.9 

17.3 
2.7 

21.0 

19.3 

39.7 
1.17 
















































































52 THE VOLATILE MATTER OF COAL. 

Table 20. —Early volatile 'products m second series of tests {heating 10 grams of air-dried 

coal to definite temperatures). 

COAL NO. 1 (ZEIGLER, ILL.). 


Temperature of furnace.°C.. 

600. 

750. 

900. 

Test No. 

155 

157 

166 

167 

168 

174 

175 

189 

Highest temperature in coal.°C.. 

400 

400 

550 

550 

550 

700 

700 

700 

Time to reach highest tempera- 









ture.minutes.. 

8.7 

8.3 

7.0 

6.0 

7.0 

5.0 

5.0 

4.5 

Tar ..percent.. 

(«) 


6.6 

7.2 


7.0 

7.2 


Water.do_ 

(a) 


14.3 

13.9 


15.7 

14.6 


Gas at 25° C.cubic centimeters.. 

^ 149 

152 

632 

696 

663 

1,480 

1,545 

1,680 

Composition of gas: 









As collected— 









CO 2 . 

12.9 

12.8 

6.8 

7.3 

8.4 

6.0 

6.2 

5.5 

Illuminants. 

3.1 

3.4 

3.0 

3.3 

3.3 

2.9 

3.3 

3.7 

0. 

.5 

.4 

.2 

.4 

0 

.5 

.2 

0 

CO. 

7.1 

7.9 

11.9 

12.3 

11.9 

14.6 

13.8 

14.3 

CH 4 , C 2 H 6 , etc. 

20.8 

20.9 

38.3 

' 37.4 

38.0 

30.0 

29.2 

27.8 

H. 

.3 

2.1 

17.9 

17.9 

16.7 

39.1 

34.7 

37.7 

N. 

55.3 

52.5 

21.9 

21.4 

21.3 

6.9 

12.6 

11.0 

Computed to 0 and N free basis— 









CO 2 . 

29.0 

27.3 

8.7 

9.3 

10.6 

6.5 

7.1 

6.2 

Illuminants. 

7.0 

7.2 

3.8 

4.2 

4.2 

3.1 

3.8 

4.2 

CO. 

16.1 

16.9 

15.3 

15.8 

15.1 

15.8 

15.9 

16.1 

CH 4 , C 2 H 6 , etc. 

47.3 

44.1 

49.1 

47.9 

48.3 

32.4 

33.4 

31.2 

H. 

.6 

4.5 

23.1 

22.8 

21.8 

42.2 

39.8 

42.3 

Value of n in CnH 2 u +2 . 

1.33 

1.43 

1.21 

1.20 

1.22 

1.19 

1.19 

1.18 


a Tar and water determinations not made at 600° in this series. 


COAL NO. 3 (CONNELLSVILLE, PA.). 


Temperature of furnace.°C.. 

600. 

750. 

900. 

Test No. 

150 

151 

152 

163 

164 

165 

172 

173 

Highest temperature in coal.°C.. 

400 

400 

400 

550 

550 

550 

700 

700 

Time to reach highest tempera- 









ture.minutes.. 

7.0 

8.7 

7.5 

8.0 

7.0 

7.5 

6.3 

6.3 

Tar.per cent.. 




9.0 

9.9 

9.0 

12.0 

12.0 

Water.. . .do_ 




5.0 

4.3 

4.8 

4.5 

4.9 

Gas at 25° C.cubic centimeters.. 

88 

79 

99 

775 

847 

830 

1,740 

1,810 

Composition of gas: 









As collected— 









CO 2 . 

5.4 

5.8 

4.9 

3.3 

2.4 

2.7 

2.1 

2.5 

Illuminants. 

3.6 

2.8 

3.0 

5.5 

5.5 

5.5 

6.2 

6.4 

0. 

0 

.3 

.6 

.5 

.1 

.4 

0 

0 

CO. 

2.1 

2.2 

2.9 

4.6 

4.6 

4.1 

6.2 

7.1 

CH 4 , CgHe, etc. 

21.3 

20.4 

20.3 

47.7 

50.4 

49.8 

40.6 

38.5 

H. 

4.4 

1.4 

1.7 

17.1 

18.8 

18.6 

35.6 

36.2 

N. 

63.2 

67.1 

66.6 

21.3 

18.2 

18.9 

9.3 

9.3 

Computed to 0 and N free basis— 









CO 2 . 

14.6 

17.8 

14.9 

4.1 

3.0 

3.3 

2.3 

2.8 

Illuminants. 

9.9 

8.5 

9.1 

7.1 

6.8 

6.8 

6.9 

7.1 

CO. 

5.8 

6.7 

8.8 

5.9 

5.4 

5.1 

6.9 

7.8 

CH^, C 2 H 6 , etc. 

57.8 

62.7 

62.0 

60.1 

62.2 

61.8 

44.7 

42.4 

H. 

11.9 

4.3 

5.2 

22.8 

22.6 

23.0 

39.2 

39.9 

Value of n in CnH 2 n +2 . 

1.63 

1.42 

1.54 

1.27 

1.26 

1.29 

1.18 

1.19 








































































DETAILED DATA OF TESTS. 


53 


Table 20 .—Early volatile products in second series of tests {heating 10 grams of air-dried 

coal to definite temperatures) —Continued. 

COAL NO. 16 (POCAHONTAS). 


Temperature of furnace.°C.. 

600. 

750. 

900. 

Test No. 

153 

156 

159 

161 

162 

176 

177 

Highest temperature in coal.°C.. 

400 

400 

400 

550 

550 

700 

700 

Time to reach highest temperature, .minutes.. 

8.0 

8.0 

8.5 

7.3 

7.3 

5.8 

5.8 





3.7 

3 5 

6 6 

7 1 

Water.r...do_ 




2.2 

2 3 

2 9 

2 5 

Gas at 25° C.cubic centimeters.. 

67 

62 

77 

647 

659 

1,650 

1,630 

Composition of gas: 








As collected— 








COj. 

3.4 

2.6 

4.0 

1.9 

1.8 

1.6 

1.5 

Illuminants. 

2.0 

2.2 

2.1 

3.7 

3.9 

4.1 

4.0 

0. 

.3 

.3 

.8 

.6 

.4 

.5 

0 

CO. 

1.8 

1.1 

1.6 

3.0 

2.7 

3.7 

4.5 

CH^, CjHs.etc. 

16.1 

13.5 

16.5 

48.2 

46.8 

39.2 

39.2 

H. 

1.0 

3.4 

1.1 

21.2 

21.2 

39.8 

40.5 

N. 

75.4 

76.9 

73.9 

21.4 

23.2 

11.1 

10.3 

Computed to 0 and N free basis— 








CO 2. 

13.8 

11.4 

15.8 

2.5 

2.4 

1.8 

1.7 

Illuminants. 

8.1 

9.5 

8.2 

4.8 

5.1 

4.6 

4.4 

CO. 

7.3 

5.0 

6.3 

3.9 

3.5 

4.2 

5.0 

CH 4 , CjHs, etc. 

66.7 

59.2 

65.4 

61.8 

61.2 

44.3 

43.7 

H. 

4.1 

14.9 

4.3 

27.0 

27.8 

45.1 

45.2 

Value of n in CnHin+a. 

1.54 

1.71 

1.55 

1.21 

1.27 

1.15 

1.15 


COAL NO. 11 (DIETZ, WYO.). 


Temperature of furnace.°C.. 

600. 

750. 

900 .0 

Test No. 

158 

160 

169 

170 

171 

178 

179 

182 

Highest temperature in coal.°C.. 

400 

400 

550 

550 

550 

700 

700 

700 

Time to reach highest tempera- 









ture.minutes.. 

10.2 

10.0 

7.0 

6.0 

6.5 

3.7 

3.7 

3.7 

Tar .percent.. 



3.8 

3.8 


2.9 

3.7 


W at.er.do_ 



21.0 

21.3 


23.1 

22.1 


Gas at 25° C.cubic centimeters.. 

408 

406 

1,048 

1,018 

1,100 

1,990 

2,050 

2,000 

Composition of gas: 









As collected— 









CO,. 

42.0 

41.6 

25.6 

25.8 

25.6 

17.5 

16.9 

17.0 

Illuminants. 

2.8 

2.4 

2.6 

2.6 

2.5 

2.3 

2.1 

2.3 

0 . 

.1 

.4 

.4 

.3 

.2 

.2 

.4 

.2 

CO. 

14.5 

14.0 

17.3 

17.7 

17.3 

21.5 

21.4 

21.2 

CH 4 , CjHe, etc. 

10.7 

10.1 

21.5 

20.3 

19.7 

17.5 

14.7 

15.8 

H..:. 

1.2 

.9 

17.4 

18.0 

18.2 

33.7 

34.5 

33.4 

N. 

28.7 

30.6 

15.2 

15.3 

16.5 

7.3 

10.0 

10.1 

Computed to 0 and N free basis— 









CO 2 . 

59.2 

60.3 

30.3 

30.5 

30.7 

18.9 

18.9 

18.9 

Illuminants. 

3.9 

3.5 

3.1 

3.1 

3.1 

2.5 

2.3 

2.6 

CO. 

20.4 

20.3 

20.5 

20.9 

20.8 

23.2 

23.9 

23.6 

CH 4 , C 2 H 6 , etc. 

14.8 

14.6 

25.5 

24.0 

23.6 

18.9 

16.4 

17.6 

H..1.;. 

1.7 

1.3 

20.6 

21.5 

21.8 

36.5 

38.5 

37.3 

Value of n in CnHsn+z. 

1.48 

1.56 

1.22 

1.25 

1.29 

1.21 

1.39 

1.28 


a Tests on coal No. 11 at 900® were run on coarsely-powdered material (between 10 and 20 mesh) In 
order to avoid mechanical loss. 










































































54 


THE VOLATILE MATTER OF COAL. 


Table 20. —Early volatile 'products in second series of tests {heating 10 grams of air-dried 
coal to definite temperatures) —Continued. 

COAL NO. 18 (DIAMONDVILLE, WYO.) 


Temperature of furnace."C.. 

600. 

750. 

900. 

Test No. 

225 

225a 

185 

186 

180 

181 

Highest temperature in coai.°C.. 

400 

400 

550 

550 

700 

700 

Time to reach highest temperature 







.minutes.. 

6.5 

7.0 

5.5 

6.2 

5.0 

5.0 

Tar.per cent.. 



11.6 

11.6 

11.2 

10.4 

Water.. . .do_ 



11.3 

11.0 

11.6 

12.2 

Gas at 25"C.cubic centimeters.. 

228 

206 

943 

925 

1,900 

1,950 

Composition of gas: 







As collected— 







COi. 

14.7 

15.7 

9.5 

8.7 

7.5 

7.2 

Illuminants. 

5.1 

4.7 

7.2 

6.5 

7.7 

8.0 

0. 

.4 

.8 

.3 

.6 

.1 

.1 

CO. 

9.8 

8.6 

14.3 

14.5 

16.7 

16.1 

CH4, CjHe, etc. 

22.9 

19.3 

37.9 

36.6 

29.2 

28.5 

H. 

2.0 

2.6 

14.9 

16.0 

28.9 

30.5 

N. 

45.1 

48.3 

15.9 

17.1 

9.9 

9.6 

Computed to 0 and N free basis— 







CO2. 

27.0 

30.8 

11.3 

10.5 

8.3 

8.0 

Illuminants. 

9.4 

9.2 

8.6 

7.9 

8.5 

8.8 

CO. 

18.0 

16.9 

17.1 

17.6 

18.6 

17.8 

CH4,C2H6,etc. 

42.0 

37.9 

45.2 

44.5 

32.5 

31.6 

H. 

3.6 

5.2 

17.8 

19.5 

32.1 

33.8 

ValueofnlnCnHjn+2. 

1.55 

1.23 

1.26 

1.31 

1.23 

1.28 


COAL NO. 10 (PAGE, W. VA.) 


Temperature of furnace.®C.. 

600. 

750. 

900. 

Test No. 

224 

224a 

187 

188 

190 

183 

184 

Highest temperature in coal.*C.. 

400 

400 

550 

550 

550 

700 

700 

Time to reach highest temperature .minutes.. 

6.7 

6.5 

7.0 

6.5 

6.7 

6.0 

6.0 

Tar.per cent.. 



11.5 

12.8 

10.4 

12.0 

12.2 

Water.do.. 



5.1 

4.7 

4.8 

4.9 

4.8 

Gas at 25° C.cubic centimeters.. 

136 

136 

975 


995 

2,005 

1,960 

Composition of gas: 






As coliected— 








COi. 

4.6 

5.4 

3.4 

2.9 

3.4 

2.4 

2.4 

Illuminants. 

3.8 

3.8 

6.9 

5.7 

6.3 

7.6 

7.1 

0. 

1.0 

.7 

.2 

3.5 

.4 

.1 

.1 

CO. 

2.7 

2.2 

4.8 

4.0 

5.1 

7.1 

6.6 

CH4, CjHe, etc. 

26.3 

22.1 

47.5 

40.0 

48.6 

35.6 

37.8 

H. 

2.2 

5.7 

20.7 

18.2 

21.0 

37.7 

36.5 

N. 

59.4 

60.1 

16.5 

25.7 

15.2 

9.5 

9.5 

Computed to 0 and N free basis— 








(5o2. 

11.6 

13.8 

4.1 

4.1 

4.0 

2.7 

2.7 

Illuminants. 

9.6 

9.8 

8.3 

8.1 

7.5 

8.4 

7.9 

CO... 

6.8 

5.6 

5.8 

5.6 

6.0 

7.9 

7.3 

CH4,C2H6,etc. 

66.4 

56.7 

57.0 

56.5 

57.6 

39.3 

41.7 

H. 

5.6 

14.1 

24.8 

25.7 

24.9 

41.7 

40.4 

Value of n in CnH2n+2. 

1.53 

1.79 

1.28 

1.25 

1.24 

1.22 

1.16 


GENERAL SUMMARY. 

The investigations described in this bulletin contribute data on 
the composition of the volatile products from different kinds of coal 
as evolved at different temperatures. The comparatively large 
amounts of inert constituents such as COj and water in the products 
from certain western coals; the large amounts of higher methane 
hydrocarbons, such as ethane, in the products at moderate tem¬ 
peratures, particularly from the Appalachian coals; and the larger 
amounts of gas and tarry vapors produced quickly at moderate 
temperatures from the younger western coals are the main features 
of the results. The bearing of these results on smoke-producing 


































































GENERAL SUMMARY. 


55 


tendencies, on studies of the nature of coal substance, and on the 
calculation of heat value from ultimate analysis is brought out in 
the foregoing pages. It has been shown that certain bituminous 
coals of the West are well adapted to the manufacture of a high-grade 
illuminating gas and of other by-products of coking, notably ammonia. 

Any statement as to the character of the gases or volatile products 
evolved from coal at specified temperatures has little value unless 
it is accompanied by a clear description of the conditions prevailing 
and particularly of the points at which temperatures were taken 
and of the mass of coal which was heated. The temperature varies 
throughout the mass and is affected by the rate and time of heating. 
Temperatures outside of the containing vessel produce different 
temperatures in the coal itself according to the kind of vessel and the 
time of heating. The distance of the vessel from the point where 
temperatures are read influences the difference between the observed 
temperature and that of the coal within the vessel. 

It is expected that these investigations will be continued and that 
the laboratory results will be correlated with experiments on furnaces 
and gas producers in operation. The work will include the examina¬ 
tion of the composition of ^ases at various points and the study of 
losses through incomplete combustion. Further laboratory work 
will be undertaken for the study of the effect of heating the same coal 
to certain temperatures at different rates, and it is planned to extend 
the investigation to a greater variety of coals. 


56 


THE VOLATILE MATTEL OF COAL. 


ADDENDA. 

SMOKE-PRODUCING PRODUCTS OF HEATED POWDERED COAL. 

From the experimental data given on pages 32 to 40, the following table has been 
compiled to show the comparative amounts of smoke-producing volatile products 
obtained by heating for 10 minutes 10 grams of different coals in powdered form. 


Table 21.— Tar and heavy hydrocarbons {smoke producers) obtained at different furnace 
temperatures, exjnessed as percentages of coal. 


Coal. 

500“ 

600“ 

700“ 

800“ 

900“ 

Connellsville, Pa. 


6.5 

15.8 

18.1 

17.5 

Zeigler, Ill. 


7.8 

9.7 

12.2 

11.9 

Sheridan, Wyo. 

ii 

2.9 

10.7 

10.7 

12.7 

Pocahontas. Va_______ 

.3 

1.4 

6.7 

11.3 

9.5 





ACCURACY OF GAS ANALYSES.® 

No greater accuracy than 0.2 per cent was attempted in any of the gas analyses, 
except in the determination of hydrogen in which 0.1 per cent accuracy was obtained. 
The coal-distillation experiments yielding the gas samples were seemingly incapable 
of such precision of control as would require any higher degree of accuracy than 0.2 
per cent in the gas analysis. 


a See page 22, 

















PUBLICATIONS ON FUEL TECHNOLOGY. 

The following Bureau of Mines publications may be obtained free 
by applying to the Director, Bureau of Mines, Washington, D. C.: 

Bulletin 1. The volatile matter of coal, by H. C. Porter and F. K. Ovitz. 1910. 
58 pp., 1 pL 

Bulletin 2. North Dakota lignite as a fuel for power-plant boilers, by D. T. Randall 
and Henry Kreisinger. 1910. 42pp.,lpl. 

Bulletin 3. The coke industry of the United States as related to the foundry, by 
Richard Moldenke. 1910. 32 pp. 

Bulletin 4. Features of producer-gas power-plant development in Europe, by 
R. H. Fernald. 1910. 27 pp., 4 pis. 

Bulletin 5. Washing and coking tests of coal at Denver, Colo., July 1, 1908, to 
June 30, 1909, by A. W. Belden, G. R. Delamater, J. W. Groves, and K. M. Way. 
1910. 62 pp. 

Bulletin 6. Coals available for the manufacture of illuminating gas, by A. H. White 
and Perry Barker, compiled and revised by H. M. Wilson. 1911. 77 pp., 4 pis. 

Bulletin 7. Essential factors in the formation of producer gas, by J. K. Clement, 
L. H. Adams, and C. N. Haskins. 1911. 58 pp., 1 pi. 

Bulletin 8. The flow of heat through furnace walls, by W. T. Ray and Henry 
Kreisinger. 1911. 32 pp. 

Bulletin 12. Apparatus and methods for the sampling and analysis of furnace gases, 
by J. C. W. Frazer and E. J. Hoffman. 1911. 22 pp. 

Bulletin 13. Resume of producer-gas investigations, October 1, 1904, to June 30, 
1910, by R. H. Fernald and C. D. Smith. 1911. 393 pp., 12 pis. 

Bulletin 14. Briquetting tests of lignite, at Pittsburgh, Pa., 1908-9, with a chapter 
on sulphite-pitch binder, by C. L. Wright. 1911. 64 pp., 11 pis. 

Bulletin 16. The uses of peat for fuel and other purposes, by C. A. Davis. 1911. 
214 pp., 1 pi. 

Bulletin 18. The transmission of heat into steam boilers, by Henry Kreisinger and 
W. T. Ray. 1912. 180 pp. 

Bulletin 19. Physical and chemical properties of the petroleums of the San Joaquin 
Valley, Cal., by I. C. Allen and W. A. Jacobs, with a chapter on analyses of natural 
gas from the southern California oil fields, by G. A. Burrell. 1911. 60 pp., 2 pis. 

Bulletin 21. The significance of drafts in steam-boiler practice, by W. T. Ray and 
Henry Kreisinger. 64 pp. Reprint of United States Geological Survey Bulletin 367. 

Bulletin 23. Steaming tests of coals and related investigations, September 1, 1904, 
to December 31, 1908, by L. P. Breckenridge, Henry Kreisinger, and W. T. Ray. 
1912. 380 pp., 2 pis. 

Bulletin 24. Binders for coal briquets, by J. E. Mills. 56 pp. Reprint of United 
States Geological Survey Bulletin 343. 

Bulletin 27. Tests of coal and briquets as fuel for house-heating boilers, by D. T. 
Randall. 44 pp., 3 pis. Reprint of United States Geological Survey Bulletin 366. 

Bulletin 28. Experimental work conducted in the chemical laboratory of the 
United States fuel-testing plant at St. Louis, Mo.” January 1, 1905, to July 31, 1906, by 
N. W. Lord. 51 pp. Reprint of United States Geological Survey Bulletin 323. 

Bulletin 29. The effect of oxygen in coal, by David White. 80pp., 3 pis. Reprint 
of United States Geological Survey Bulletin 382. 

Bulletin 30. Briquetting tests at the United States fuel-testing plant at Norfolk, 
Va., 1907-8, by C. L. Wright. 41 pp., 9 pis. Reprint of United States Geological 
Survey Bulletin 385. 

Bulletin 31. Incidental problems in gas-producer tests, by R. H. Fernald, C. D. 
Smith, J. K. Clement, and H. A. Grine. 29 pp. Reprint of United States Geological 
Survey Bulletin 393. 

Bulletin 32. Commercial deductions from comparisons of gasoline and alcohol tests 
on internal-combustion engines, by R. M. Strong. 38 pp. Reprint of United States 
Geological Survey Bulletin 392. 


57 


58 


THE VOLATILE MATTER OF COAL. 


Bulletin 33. Comparative tests of run-of-mine and briquetted coal on the torpedo 
boat Biddle, by W. T. Ray and Henry Kreisinger. 50 pp. Reprint of United States 
Geological Survey Bulletin 403. 

Bulletin 34. Tests of run-of-mine and briquetted coal in a locomotive boiler, by 
W. T. Ray and Henry Kreisinger. 33 pp. Reprint of United States Geological 
Survey Bulletin 412. 

Bulletin 35. The utilization of fuel in locomotive practice, by W. F. M. Goss. 29 
pp. Reprint of United States Geological Survey Bulletin 402. 

Bulletin 36. Alaskan coal problems, by W. L. Fisher. 1911. 32 pp., 1 pi. 

Bulletin 37. Comparative tests of run-of-mine and briquetted coal on locomotives, 
including torpedo-boat tests, and some foreign specifications for briquetted fuel, by 
W. F. M. Goss. 58 pp., 4 pis. Reprint of United States Geological Survey Bulletin 
363. 

Bulletin 39. The smoke problem at boiler plants, a preliminary report, by D. T. 
Randall. 31 pp. Reprint of United States Geological Survey Bulletin 334, revised 
by S. B. Flagg. 

Bulletin 40. The smokeless combustion of coal in boiler furnaces, with a chaptef 
on central heating plants, by D. T. Randall and H. W.. Weeks. 188 pp. Reprint or 
United States Geological Survey Bulletin 373, revised by Henry Kreisinger. 

Bulletin 41. Government coal purchases under specifications, with analyses for 
the fiscal year 1909-10, by G. S. Pope, with a chapter on the fuel-inspection laboratory 
of the Bureau of Mines, by J. D. Davis. 1912. 97 pp., 3 pis. 

Bulletin 43. Comparative fuel values of gasoline and denatured alcohol in internal- 
combustion engines, by R. M. Strong and Lauson Stone. 1912. 243 pp., 3 pis. 

Bulletin 49. Smoke abatement and city smoke ordinances, by S. B. Flagg. 1912. 
55 pp. 

Bulletin 55. The commercial trend of the producer-gas power plant in the United 
States, by R. H. Fernald. 1913. 93 pp., 1 pi. 

Technical Paper 1. The sampling of coal in the mine, by J. A. Holmes. 1911. 

18 pp. 

Technical Paper 2. The escape of gas from coal, by H. C. Porter and F. K. Ovitz. 
1911. 14 pp. 

Technical Paper 3. Specifications for the purchase of fuel oil for the Government, 
with directions for sampling oil and natural gas, by I. C. Allen. 1911. 13 pp. 

Technical Paper 5. The constituents of coal soluble in phenol, by J. C. W. Frazer 
and E. J. Hoffman. 1912. 20 pp., 1 pi. 

Technical Paper 8. Methods of analyzing coal and coke, by F. M. Stanton and 
A. C. Fieldner. 1912. 21 pp. 

Technical Paper 9. The status of the gas producer and of the internal-combustion 
engine in the utilization of fuels, by R. H. Fernald. 1912. 42 pp. 

Technical Paper 10. Liquefied products from natural gas; their properties and 
uses, by I. C. Allen and G. A. Burrell. 1912. 23 pp. 

Technical Paper 16. Deterioration and spontaneous combustion of coal in storage, 
a preliminary report, by H. C. Porter and F. K. Ovitz. 1912. 14 pp. 

Technical Paper 20. The slagging type of gas producer, with a brief report of 
preliminary tests, by C. D. Smith. 1912. 14 pp., 1 pi. 

Technical Paper 25. Methods for the determination of water in petroleum and 
its products, by I. C. Allen and W. A. Jacobs. 1912. 13 pp. 

Technical Paper 26. Methods of determining the sulphur content of fuels, espe¬ 
cially petroleum products, by I. C. Allen and I. W. Robertson. 1912. 13 pp. 

Technical Paper 31. Apparatus for the exact analysis of flue gas, by G. A. Burrell 
and F. M. Seibert. 1913. 12 pp. 

Technical Paper 36. The preparation of specifications for petroleum products, by 
I. C. Allen. 1913. 12 pp. 

Technical Paper 37. Heavy oil as fuel for internal-combustion engines, by I. C. 
Allen. 1913. 36 pp. 

o 


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